Send call id for call upgrades, so that they hangup the call properly
Store imported google contacts in the contacts db
Fix a typo in the CONTRIBUTING file
Depend on python 2.7 explicitely.

Otherwise this can install the virtualenv with python 3.X.
Add a "clean" makefile directive.
Add some code documentation and fix a few typos.
Merge pull request #300 from ametaireau/minor-fixes

Minor fixes
Merge pull request #298 from Standard8/call_upgrade_fix

Send call id for call upgrades, so that they hangup the call properly, r=@dmose
Improve the function name for addBatch (replaceSourceContacts) and improve test error handling
Add documentation for replaceSourceContacts and improve its readability.
Add frontend test for updateContactsFromSource
Improve error handling for replaceSourceContacts
Handle null callbacks correctly
Merge pull request #299 from Standard8/google_import_db

Store imported google contacts in the contacts db