Corrected error in example usage in README file
Added verbose_name to APNSDevice registration id. Corrected PEP 8 indentation problems
More PEP8 corrections
Separated model managers in managers.py file. More PEP 8 indentation problems solved
Changed Apple documentation link on apns.py header
Modified gcm_send_message in order to send json format. This allow send nested data. If  it send nested data in current version, it fails when it tries to encode the value on 'd.key=value' structure.
Refactored whole gcm message sending structure. Now it's in object oriented style. If extra params are neded, it uses the kwargs instead
Refactored whole apns message sending structure. Also in object oriented style and with kwargs magic. Updated README file