pickup changes for actionproxy action current directory /action

Update base images to openwhisk/dockerskeleton:1.3.2. and adjust tests for upstream changes.

This version contains important fixes to limit the number of connections made during bootstrapping

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

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.

* Add kafka_python library to the Python action runtime

* Update doc and Python package sniff test

Please squash into previous commit

Additionally:
    - pinned versions
    - tests
    - added to reference doc

- Add the requests module to the python container
- Add tests to assert that module installation for the python container works as expected.

Solves #1190

Reduce image size for docker actions skeleton from 619.8MB to 86.78MB.
This makes the example docker image size equally smaller.
Use the base image for python actions but not Swift since the latter not yet ready for a diet.

Adjust docker sdk deployment to reference image from Docker Hub.

Rebase swift(3) actions using new action proxy and override epilogue, buil and env method to properly build binary and serialize input as required by swift actions.
Rebase python action using new action proxy.
Rename runner files to {lang/runtime}runner.py.

- whisk/scala: installing jre instead of jdk and nuke scala
- better base images: buildpack-deps
- drop maven from kafka and use wget instead
- install nodejs binary directly instead of apt-get it
- @rabbah consolidated common python build steps to elevate docker caching

`pip install gevent` compiles it locally, which takes forever

Python action taking so long that builds are timing out including Travis where it times out from global timeout which is out of our control.

Bump docker timeout to 420 seconds.

Fix hello python sample action to fit the same pattern as the js and swift actions.