Removed excess endif()

Ruby: generated foo.proto -> foo_pb.rb instead of foo.rb.

This brings us more into line with other langauges, and makes it more
obvious when we are requiring protobuf generated code.

Add a script to build protoc zip packages.

[ci skip]

Change-Id: Ia0e0bf3bb6bd24633dc8f294318bb20ac837f8b9

Ruby: translate package names from snake_case -> PascalCase.

Added unit test for PascalCasing package names in Ruby.

Added new file to ruby_EXTRA_DIST.

A series of improvements:

- Improved Protobuf module compatibility (disabled by default);
- Hide advanced settings;
- Added build tree configuration;
- Added build of examples.

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)

* `csharp_options`: Added `Options` to encapsulate generator options.
   Supported options for now - file_extension, base_namespace
* `{Blah}Generator`: Now accept `Options*` as parameter to constructor
* `csharp_generator.cc`: Parse and populate options
* `Makefile.am`: Added `csharp_options.h`
* `extract_includes.bat.in`: Added `csharp_options.h`

Refactoring code to two commits. This is the first commit

Java files are moved to un-do the hack in the prevous commit, which
moved the java files to the original position for integration.

Change-Id: I6fa9f1b65d6c06b891aabf3f3d868364d74d727d

This changes csharp_names.h, which will require a corresponding change in GRPC.

In anticipation of PR #753 getting merged we'll change this back. However until that PR gets merged the old value "BUILD_TESTS" is really needed.