Adds the ability to add pluggable implementations for defined Service Provider Interfaces (SPI). The implementation to load is chosen via configuration.

First set of plug-points are:
- ArtifactStoreProvider
- MessagingProvider

This allows actions to set/retrieve global variables as an additional optimization during container reuse.

* rename namespace to global_context

* Implement PHP 7.1 kind
* Add tests for PHP 7.1 action
* Add PHP action documentation

Build the Docker container from php:7.1-alpine and implement the HTTP
server using PHP's built in server.

Note that when using a zip file, the router requires that the `main`
function is stored in `index.php`.

Note about the runner:
The runner sets the exit code to 1 if it has set the last line of stdout
to a string suitable for presentation to the user. Therefore, if the
exit code is not one, then display a generic message.

If there's a runtime error in the action (i.e. not spotted by linter),
then looking for the main() function will find it. Render the error to
the logs so that the user knows what's happened.

Note about vendor folder in a PHP zip:
If the PHP vendor file has a vendor directory, then this directory needs
to be used rather than the one supplied in the action container.

To do this, we require src/vendor/autoload.php which will exist if the
zip file contains it. For the two cases where (1) zip file does not contain a
vendor folder, or (2) when running a non-binary code action, we move the
container's vendor folder into src/.

* Add documentation for docker for mac (#1431)
* Replace akka-http client to play-ws client (temporarily)
* Introduce docker-machine environment

* Experimental branch for 2079, uses ibm swift ubuntu image for 3.1

* Fixes issue #2079, add Swift 3.1.1 runtime kind, update Swift dependencies for Watson SDK, KituraNet, SwiftyJson

* add apache license

* Fix swift311 location and catch docker brake

The location of the swift binary for 311 is now in /usr/bin/swift
Need to catch docker errors when building by usig && instead of ;

* new zip for new swift311 runtime

* Install/upgrade six module before installing other dependencies in travis

* Explicitly upgrade six in action images

* make travis fast again

* Refactor Unicode test to be able to exclude python and swift

* color term expect gradlew

* do apache license header

* Use abstract class

* exclude Java

* remove initializer from abstract class

A proxy that wraps a Container. It is used to keep track of the lifecycle
of a container and to guarantee a contract between the client of the container
and the container itself.

The contract is as follows:
1. Only one job is to be sent to the ContainerProxy at one time. ContainerProxy
   will delay all further jobs until the first job is finished for defensiveness
   reasons.
2. The next job can be sent to the ContainerProxy after it indicated capacity by
   sending NeedWork to its parent.
3. A Remove message can be sent at any point in time. Like multiple jobs though,
   it will be delayed until the currently running job has finished.

This includes a much nicer output, especially with parallel jobs.

Also fixes bad redirect in build script.

* API GW V2 CLI - Add 'wsk api' command
- Support both 'wsk api-experimental' and 'wsk api' commands (separate PR wil deprecate `api-experimental`)
- 'wsk api' command requires that the target action exist and that it's a web action

* API GW V2 CLI - 'wsk api' tests
* Add "COMING SOON" label to 'wsk api' help
* API update needs additional param
* Reduce travis test execution time

Also, change working directory for Python actions to allow relative path access to file system.

Re-enable build swift/python containers (for tests to run).
Add unicode unit test for swift action container.
Allow for reinit with swift for use with invoke.py.
Fix unicode regression for swift actions.
Refactor unicode tests to add coverage - now also for base action container.
Set string encoding to utf-8 for swift action proxy.
Rewrite result extraction to avoid splitting and printing logs one line at a time.
Skip decoding when process output is a string; already utf-8.

Consolidate base64 encoding in CLI; remove Jar field in exec.

Update tests to work in both Python 2 and Python 3.
Rename pythonaction to python3action for container image name for clarity.
Add tests for python:2 and python:3.
Add image names for all the actions. Rename javaaction to java8action for consistency.

* Decode subprocess output bytes to text in actionproxy.

* Update swift3runner build step to capture stdout/stderr,
and decode if necessary.

Remove license headers from just test/dat path

Remove subtypes.

Move exec utils for image construction to singleton.

Rebase

# This is the 1st commit message:
Update header to comply with Apache requirements

Additionally, provide proper header (with script description) using PEP8 compliant string literal.

# The commit message #2 will be skipped:

#	Update box-upload.py

# The commit message #3 will be skipped:

#	Update invoke.py

# The commit message #4 will be skipped:

#	Update actionproxy.py

- Remove unused dependencies
- Define dependencies as compile time to be able to include them from other projects
- Standardize layout

* Bumping restassured version

* Update gitignore to include .cache-tests

Add manifest schema.
Add utilities to read Exec runtimes from manifest.
Add runtimes manifest to ansible group vars.
Write out manifest to whisk.properties and make available through WhiskConfig.

The change in #1946 introduced a regression such that it did not allow for Node.js zipped actions which contain an index.js but not a package.json. This is a valid configuration and should be supported.

Using the Windows Explorer method of creating zip actions results in an incorrect zip structure. OW requires that package.json be found at the root of the zip, while the Explorer action insists on putting everything inside a top-level folder inside the zip.

Return an explicit error when package.json is not found at the root of a zipped action.

* Normalize initializer for all execs.

* Handle empty code for blackbox.

* Do not include code if null.

Refactoring of init method into an init-from-source and init-from-zip.
Support a zip file containing more than one python file.
The zip file must contain a file called __main__.py that defines a "main" method.

Log an error when python zip does not include required file.