Fix the bug in following scenario:  

gmock is downloaded successfully while gtest not. Resuming "autogen.sh",
the gtest won't be downloaded. And following error will occur:  

$ ./autogen.sh
+ autoreconf -f -i -Wall,no-obsolete
aclocal: error: configure.ac:1: file 'gtest/m4/acx_pthread.m4' does not exist
autoreconf: aclocal failed with exit status: 1

Move parse frame array to the Map object

* Add php support for Timestamp.

* Fix comments

This makes the frame stack per-parser, and per-thread.  Fixes #3250

* Add any support in php runtime.

* Remove unused file in config.m4

* Fix comments

* Fix error for tsrmls build

* Add newly added file to Makefile.am

Work around a bug in clang's static analyzer

Add Python 3.5, 3.6 && drop Python 2.6

Remove pre-installed softwares from prebuild steps 

Merge fixes from 3.4.x into master

Disable death tests on windows

Jenkins complains for python 2.6
DEPRECATION: Python 2.6 is no longer supported by the Python core team
ERROR: InvocationError: '/tmp/protobuf/protobuf/python/.tox/py26-cpp/bin/python setup.py -q build_py'
https://grpc-testing.appspot.com/job/protobuf_pull_request/1502/testReport/junit/(root)/python_cpp/python_cpp/

Also remove cord related code

Use message name as defined in php runtime.

Merge pull request #3535 from drivehappy/clang_warn_cleanup

Merge pull request #3494 from drivehappy/clang_warning_macro

Add Elixir protobuf and gRPC to 3rd party doc

Due to https://bugs.llvm.org/show_bug.cgi?id=34198, clang's static
analyzer emits diagnostics about leaking `container`. Doing this
assignment in two steps works around this, and shouldn't cause these
issues.

Fixing -Wexpansion-to-defined Clang warning

Fixing unused parameter warnings under Clang.

Fixing unused parameter warnings under Clang.

Remove C++11 features in io_win32.cc

- Use scoped_array instead of unique_ptr.
- Do not use string::front() and string::back()

Merge 3.4.x into master

* remove the parens from the cmp() lambda definition

https://github.com/PythonCharmers/python-future/pull/298

* remove the parens from the cmp() lambda definition

https://github.com/PythonCharmers/python-future/pull/298

Bump gemspec again

Prefer system distributed binaries/libraries.

protoc-artifacts: Bump JDK to 8u131

This reverts commit 703f414c.

* Drop Python 3.3 from testing & add Python 3.5, 3.6

Python 3.3 goes [EOL](https://docs.python.org/devguide/index.html#branchstatus) next month.

* Sync test.sh with the Python versions in tox.ini

* Define cmp() for Python 3

http://python-future.org/compatible_idioms.html?highlight=cmp#cmp

* Define cmp() for Python 3

http://python-future.org/compatible_idioms.html?highlight=cmp#cmp

Python 3 compatibility fixes: print(), long(), etc.