Fix LogicInfo parsing for string logics
clean some code
Cache apt packages on Travis.
Switch license default back to BSD, and add --best and --enable-gpl options.
Merge branch '1.3.x'

Conflicts:
	COPYING
	NEWS
	config/cvc4.m4
Fixes to stats registry
Framework for theory proof generation.  LFSC Proof generation for UF.  Proof-checking work.  Assorted fix-ups related (mostly) to proofs.
some debugging, cleanup