code cleaned following pep8
removed old code, now test works!!!!

corrected bug for py3

maybe this time will work

Corrected the difference function, now it return the difference between the edges of 2 graph.
Made a new test for the parser.
Fixed weight in json generation.
Merge branch 'master' of https://github.com/gabri94/netdiff into gabri94-master

Conflicts:
	netdiff/olsr1.py
Merge branch 'gabri94-master'
Removed redundant graph generator
Added test for "no changes" case in OLSR1
Refined Olsr1Parser
Added diff_json method to Olsr1Parser
Added Usage section in README