These changes require building new docker images and without new images
our kokoro tests are all failing.

* Fixes https://github.com/google/protobuf/issues/5031
* Fixes https://github.com/google/protobuf/issues/5037

* Add kokoro config for building python wheels on windows

* Move script to root

* Debug

* Debug

* Change working directory

* Add msbuild to path

* Debug

* Fix python dir name

* Debug

* Move artifacts to targeted directory

* Update artifact directory

* Debug

* Debug

* Automatic generation of version

* Reduce file numbers

Changes:
1. Remove stuff no longer needed. Lots of the heavy lifting were there
because we were running our own jenkins cluster and had to manage all
the test logs ourselves. Now they are useless.
2. Change "-j2" to "-j4" to speed up the test a little bit. Kokoro
machines have 4 logic CPUs according to their spec.

* Add config for building python wheel on mac

* Specify os name

* Clean up venv

* Debug

* Recover old path

* Add config for building python wheel

* Update submodules

* Fix setup.py to use c++11

* Fix syntax error

* Fix syntax error

* Add dir for artifact

* Update artifact dirctory

* Remove python 3.3

* Clean up virtual env

* Clean up env

* Test environment

* Test env variable

* Automatic update version number

* Remove dependency on python-wheel branch

This reverts commit c02346c72aafd1826b0397dbbce4ce04bf252f50.

This was fairly straightforward using the existing build-protoc.sh
script. The only problem I ran into was that the x86 Docker builds
create output directories owned by root, which caused some permission
issues. Fortunately it was easy to get around that just by doing those
Docker builds last.

* upgrade dotnet SDK to 2.1.3 on kokoro linux

1. Added C++ tests under the release docker image.
2. Cleaned up tests.sh and removed traivis stuff.

1. Added C++ tests under the release docker image.
2. Fixed a compile issue with the docker image.
3. Cleaned up tests.sh and removed traivis stuff.

* Install rake compiler

* Add kokoro config to build ruby gem on linux

* Rename from linix to linux

* Fix prepare_build.sh name

* Clean up

* Install bundler

* Install bundler

* Use c99 in order to build gem on mingw-32 on ruby 2.0.0

See https://github.com/rake-compiler/rake-compiler-dock/issues/4

* Move c99 config to extcofig.rb

* Add files to build ruby artifact for mac on kokoro

* Move ruby specific stuff to ruby dir

This configuration builds both 32-bit and 64-bit binaries for Mac OS X.
One thing I had to change was to increase our minimum supported version
for 10.7 to 10.9, because 10.9 (Mavericks) appears to be the earliest
version supporting C++11.

This should make it easy to automatically build 32-bit and 64-bit
Windows protoc binaries.