- Fixed the concatenation problem. NOT sure of the last part in
	build_nfa, most probably it should have no effect (as only
	one pair will remain for concatenation)
- TODO: Escape sequences in input & range operator []
Merge branch 'master' of https://github.com/nullstring/compiler
- Autoconflict resolution by GIT
- Coded the range operator for simple case like [a-z]
- Need to test it & insert the escape sequences in the regex
Merge branch 'master' of https://github.com/nullstring/compiler