* [RPC] Refactor, introduce tracker

* [RPC] Change RPC hand shake convention, always get remote key.

* fix lint

* Update DMLC core most recent version

* Modify runtime to minimize io when building for SGX

* Add SGX example app

* Prefer streaming versions of packed_func function

This reverts commit 12d15704d7f5d30cff7540f1fd16be64c6baca68.

* [RUNTIME] Refactor extension type handling, now it is header only

* [RPC][JVM] Remove binary dist gradle from repo

* fix header

* [RUNTIME] Enable ext_dev type for quick plugin of device

* [TEST] Update testcase to cover all computation

* [DOCS] How to deploy TVM Modules

* More comments

* [RUNTIME] Enable extension type to PackedFunc.

* More comments

* [DOCS][APP] Add Example for C++ deployment

* fix lint

* [APP] Android RPC first version

* [APP] Android RPC build jni automatically

* [APP] Android OpenCL RPC tested on real devices

* [APP] optimize android app interface. add ndk compile tool

* add ndk compile tool

* [APP] fix android app thread crash; add android test script

* [APP] android app - show alert dialog and disconnect when error occurs

* fix ndk build script code lint

* fix ndk build default argument

* ndk script build remove shell=True. disable android app screen orientation

* [EXECUTOR] Split graph_executor to header file and (runtime) source file

* Fix

* [PASS] Enhance LayoutTransform pass

* Fix

* Fix Compilation

* Refactor

* Refactor

* doc

* fix

* add file

* [PASS] Improve graph fusion

* Change fusion center to segment head

* Use 'master' to identity the schedule node

* Make things compact

* Fix