Added python 3.3 to test-suite
Removed unused import
Removed unused import
Migrated to EAFP for attribute checking
Bumped version of ModulePickling for migration to hashlib
Added py33 environment to tox
Fixed issue with package importing on python 3.3
Fixed exception raised during cache reading
Switched cache hashing to hashlib
In python 3.3 the hash function is returning different hashes during
different executions of the application.
Moved package checking logic in follow_str function
Created find_module compatibility helper method
Conditional implementation of load_module for python 3.3