Removed all unnecessary files from the Xcode project

Change-Id: I60c20e184f51906e6e2fb3880d593584aac0e2fb
Tested: on OS X
Merge remote-tracking branch 'upstream/master'
Initial commit of .NET port of FlatBuffers

Include C# codegen in flatc and .NET FlatBuffer access via the
FlatBufferBuilder class
Updated ByteBuffer to no longer use streams

Modified ByteBuffer to use raw buffer directly instead of via streams.
Updated copyright info.
Updated tests & ByteBuffer guards

Updated tests to use NUnit framework; added test coverage on the
ByteBuffer implementation. Added bounds checks to ByteBuffer get/put
methods
Updated namespace

Updated Namespace from FlatBuffersNet to simply "FlatBuffers". This is a
breaking change.
Merge with upstream

Merge of code with upstream branch. Rolled forward fixes and
modifications into the C# version
Merge with upstream