add another step in Compiler

	modified:   Compiler.hs
compiler compile lambda calculus into C

using Hantao's excellent runtime system lam_stg.h

enabled with -C option. eg ./compiler -C input/queens

result can not contain explicit functions, otherwise runtime error would
occur

	modified:   Compiler.hs
	modified:   Makefile
	modified:   input/queens
	new file:   lam_stg.h