Change the XML description to unify multi dev/reg in a clean
fashion. Move the description parser to its own library. Fix
the tester and headergen tools to work with the new format and
library. Move the STMP3700/3780 descriptions to the new format
(and fixes many errors as well). Drop the hwemulgen tool
in favor on the upcoming hwstub tools revamp.
Change-Id: I7119a187aab5c8b083cc5228cb1b248ee29f184d
