travis: installation commands updated to use mirrors
requirements.txt added and travis conf file updated
python3 compatibility change: moduleregistry check for module type insted of string
requirements.txt: importlib removed
tests: imports fixed to relative imports
python3 compatibility change: moduleregistry check for module type insted of string
travis: python 3.2 and 3.3 dropped since it won't work because of django.test still uses old "except"