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.

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

* PHP: support 7.0

* Also fix in test_util.php

[skip ci]

Change-Id: I1ba6f6372a08b5796570851336e1a548602f60da

Change-Id: I3ff47358e66965cab34736eed2a477ae29f02f61

`System.identityHashCode` returns a hash that does not consider a
Message's values. This means two Messages with identical values will not
have identical hashCodes.

This patch uses the pattern from RubyMap to combine the hashCodes from
all values in a given message and produce a unique, consistent,
value-based hash.