ARM: implement vhdp
Update lang
Change a bunch of "MayHavePrefix" to "HasUnknonwPrefix".

Should be safe, I think none of these have any sane use of prefixes anyway.
Two approaches to vh2f (half-float to float): lookuptable and fast SSE
Delete the lookup table version of vh2f
Merge branch 'halffloat'

Conflicts:
	Core/MIPS/x86/CompVFPU.cpp
Merge branch 'master' of github.com:hrydgard/ppsspp
Minor cleanup