Remove dead code related to using a non-local FIFO for message passing.

Bug: 22603341

Some parts of the RS runtime were designed for a situation where the
message sender could be on a different process from the RS driver.
The code for this functionality, however, is untested and no longer
used, so we remove it for now.

- Change rsg_generator not to create RF_* and rspr_* functions for
  remote passing / playback.

- Change rsThreadIO so that it runs on a local mode only.

- Minor cleanups / documentation to rsg_generator code.

Change-Id: I99adff6f93142d47e0a471ffc80f965eaad6567f
3 files changed