ruby: Migrate all of ruby and slicc to SCons.

ruby: Migrate all of ruby and slicc to SCons.
Add the PROTOCOL sticky option sets the coherence protocol that slicc
will parse and therefore ruby will use.  This whole process was made
difficult by the fact that the set of files that are output by slicc
are not easily known ahead of time.  The easiest thing wound up being
to write a parser for slicc that would tell me.  Incidentally this
means we now have a slicc grammar written in python.