Push llvm-general into a subdirectory.

Conflicts:

	llvm-general/src/LLVM/General/Internal/FFI/Constant.h
	llvm-general/src/LLVM/General/Internal/FFI/ExecutionEngineC.cpp
	llvm-general/src/LLVM/General/Internal/FFI/MemoryBuffer.hs
	llvm-general/src/LLVM/General/Internal/MemoryBuffer.hs
Remove extraneous dependency.
split llvm-general-pure out of llvm-general