this is a commit for number 4 hofcroft algorithm

i have changee scanner.py for retrieving alphabets
i have changed automata.py for several things
i have added /testdata/dfa_x.txt for hofcroft algorithm test data
Merge branch 'master' into subset-construction

Accepted my changes - bulldozed all others. This is being done before the
pull request.

Conflicts:
	automata.py
	scanner.py