RequestPendingVendorActivity

Closes #87
- Updates DelegateActivity to use the correct RequestPendingActivity, depending on User.Type
- Updates LoginActivity to only move to the next activity *after* graph data is saved
- Adds feedback to RequestCreateActivity if a request is created
- Updated RequestMapActivity to use the sensor location (as opposed to current User location)
   + In case saveEventually() is not done
- Updates RequestPendingActivity to be a subscriber to the Request update channel
- Updates the RequestPendingClientActivity to react to Vendor-initiated request updates
- Updates the RequestPendingClientActivity to wait until request is fulfilled before publishing and updating UI
- Adds RequestPendingVendorActivity with Real-Time push updates from Client
- Adds RequestUpdateChannel, a way to subscribe and publish Request updates
- Updates vendor setter to remove data on null
- Updates the type getter to return CLIENT on null
- Updates PushUtil to use the REST API, since the Android API is incorrectly encoding the JSON passed in.
- Adds the Parse REST API key to the manifest
- Adds android async library so that we can do push via REST