added missing closing bracket for _cmakedir_desc in cmake/install.cmake:88

Add protobuf:: namespace to installed targets

Add compatibilty tests against v2.5.0

Make the CocoaPods integration tests more robust

Make protobuf-config-version.cmake.in set the required variables

Make cmake configuration file install path configurable

- Env solution doesn't seem to always work, use template pod files and copy
  them in place instead.
- Flush the pods cache before and after runs.
- Make pod install verbose to have the info incase something goes wrong.

Update protobuf-config-version.cmake.in to correctly set the required variables (PACKAGE_VERSION_EXACT, PACKAGE_VERSION_COMPATIBLE, PACKAGE_VERSION_UNSUITABLE)

Fix the cmake configuration file install path to be more standards compliant (See the description of cmake's config search behavior on https://cmake.org/cmake/help/v3.4/command/find_package.html)

Add shared schemes for the CocoaPods integration tests

Otherwise the projects have to be opened once to create user schemes for the
command line builds to work.

OS X gitignore cleanup and cocoapods integration tests

- Add an Xcode 6.3 created default iOS Project.
- Add an Xcode 6.3 created default OS X Project.
- Add Podfiles to for both that use Protobufs from within the tree.
- Add a script to run the tests (and cleanup) to help confirm the state of the
  Protobuf.podspec and sources.

Ruby oneofs: return default instead of nil for unset fields.

- Add the folder CocoaPods will add to the root folder.
- Move and expand the entries in the objectivec directory.

Export class Arena to shared library.

Fix #include in js_generator.cc

Merge beta-3 release branch again.

Integrate interanl changes

JSON format for Any message must print @type first

Fix protoc artifact pom version

This got broken in commit 6ef984af
which integrated changes from internal branch.

The commit 3b3c8abb has replaced the <>
with "" in #include statement in js_generator.cc

Added download_url to be able to upload to pypi.

Merge Beta 3 release branch into master

Update changes for lite

Remove the comments about iterator validation

As it may be implementation dependent.