Also refactored the way options are stored.

Change-Id: I709ac908cd2aba396c9c282725cf1d42ccce0882
Tested: on Linux.

Change-Id: I6600021b7ec8c486794349511232c3e604421c5b
Tested: on Linux.

- Add parse handling of .proto struct and field doc comments (enums and
their values were already handled)
- Add FBS generation handling of doc comments for structs, their
fields, enums, and their values (requires linking idl_gen_general in
the test binary build)
- Tested using test.proto|golden with doc comments added.  Xcode run of
flattest passes.

Change-Id: Idff64dd8064afba227174ab77d2c7be22d006628

This change renames a few variables to fix the build in VS 2015.

VS 2015 new warnings:
http://blogs.msdn.com/b/vcblog/archive/2014/11/12/improvements-to-warnings-in-the-c-compiler.aspx

Change-Id: Ic9c3f75ee717f0125960c813df442ed4fbcceb4a

Bug: 15777858
Change-Id: Iabef9b8c8044e593bb89510feebdee00d2f1840b
Tested: on Linux and Windows.