Implements writing FlexSym annotation sequences

[zslayton]

This PR includes 3 commits, 2 of which are simply cleanup:

• [Cleanup] a95864d Moves the macro used to provide a delegating annotation writer implementation to a central location so it can be used by both the v1_0 and v1_1 modules.
• [Cleanup] 1153aa8 Deletes an old copy of the binary 1.0 ValueWriter implementation. The file was not attached to the parent directory's module, so it wasn't causing problems, just taking up space.
• 362f212 Contains the interesting logic relevant to annotations encoding.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.