Port FlatBuffers to Go.

Implement code generation and runtime library for Go, derived from the
Java implementation. Additionally, the test suite verifies:

 - the exact bytes in the Builder buffer during object construction,
 - vtable deduplication, and
 - table construction, via a fuzzer derived from the C++ implementation.

Change-Id: Ib95a019c684891def2b50281e570b4843fea7baa

docs/source/doxyfile

@@ -748,6 +748,7 @@ INPUT = "FlatBuffers.md" \
         "Compiler.md" \
         "Schemas.md" \
         "CppUsage.md" \
+        "GoUsage.md" \
         "JavaUsage.md" \
         "Benchmarks.md" \
         "WhitePaper.md" \