python26 compatibility fix

fix format errors
fix unittests
fix tox & travis configs
CFY-1274 code cleanup
Merge pull request #63 from cloudify-cosmo/CFY-1274-py26-compatebility

python26 compatibility fix
Merge branch 'master' into CFY-1318-tosca-interfaces

Conflicts:
	cloudify/tests/test_local_workflows.py