Remove obsolete android/protocol/ directory.

This feature was never really completed, and impedes refactoring.
The corresponding sources were used to try to implement the separation
of UI and emulation engine into two separate processes, but never
truly worked. The lack of DSL to generate protocol stubs/proxies
was also very painful.

The feature could be revived in the future with a very different
implementation, if desirable.

Change-Id: I516d6627ee5d649bbcbf140b6274f1ff1b57fdd3
42 files changed