Switch to use RSCompilerDriver.

This commit is large. It does:

1. Clean-up RSScript. ScriptCached and ScriptCompiled are removed.
2. Switch to use CompilerConfig.
3. Switch to use RSInfo. MCCacheReader and MCCacheWriter are removed.
4. Update C API implementation of libbcc (i.e., bcc.cpp). Note that
   it'll be completely removed once there's no clients relying on it.

Change-Id: I9cbe9f9441f73b7c0b3b84793cb35810dd3a9f4c
23 files changed