Fix python_cpp test on Mac. Link staticly when building extension, so that the extension doesn't require installing protobuf library. (#2232)

* PHP: fix ZTS tsrm_ls errors

* Fix a few more macros

Fixed references to foreign nested messages with CommonJS-style imports

Do strict enum name checking only for proto3

There seem to already be .proto files out there that have conflicting
enum names, which will not be able to build successfully for some
languages (like C#). To prevent this problem from spreading, let's make
it an error for proto3 but just issue a warning for proto2. This fixes
issue #2179.

Added alias getFieldProto3 as used by older generated code.

Un-breaks users who have old generated code and upgrade
to the 3.1.0 release.

A bug was causing generated JSPB code with CommonJS-style imports to
refer incorrectly to nested messages from other .proto files. The
generated code would have things like "test_pb.InnerMessage" instead of
"test_pb.OuterMessage.InnerMessage". This commit fixes the problem by
correctly taking into account any message nesting.

Update README.md

Fix VS test failures.

Needed to pick up a Java dependency change and re-populate the offline
repo.

[skip ci]

Reduce test length to avoid stack overflow on VS.

"ps: StartFileDownload" is broken by a recent appveyor image update:
http://help.appveyor.com/discussions/problems/5308-ci-frequently-hangs-with-recent-image-update

Change-Id: Ia73aa8b12f77eb9bbec556a4c05310153aad97bf

Fix Visual Studio compile issues.

Change-Id: I6a5078b6bcdf4637e11c1cb9da1f74298e6fc26e

Fix default instance destructor and memory leaks