Created BillingWorker to handle message billing
Refactored imports
Renamed BillingWorker to BillingDispatcher which now extends Dispatcher
Refactored BillingDispatcher routing logic
Merge branch 'develop' into feature/issue-732-billing-router-create
yielding pause_connectors call
Moved BillingDispatcher to a new home
Revised message routing logic
Removing is_paid from the go metadata when resetting the flag
Rafactored test cases and wrote first billing test case
Added more billing related tests
Added more routing tests
Setting message tag before sending to billing
Fixed remaining billing tests
Added some tests for the BillingDispatcher
Merge branch 'develop' into feature/issue-732-billing-router-create
Merge branch 'develop' into feature/issue-732-billing-router-create
Add custom user model.
Fix go/accounts so that its tests pass.
Reference correct user model from billing.