Add Visual Feedback to Pin Submission

[milo-trujillo]

Users need to know whether their cameras have been submitted to the server. Right now we make a "vibrate" tone when the submit button is pressed, which at least lets the user know their button press was recognized. However, this gives no indication as to whether the submission has succeeded, or is lagging on a slow network.

We should provide visual feedback of progress, like a little "Your camera is being submitted" with pinwheel pop-up, until the camera is accepted or rejected by the server.

--- Update ---

Implemented on iOS on the 1.4 branch. We make a banner alert notification when a camera is successfully marked or unmarked, if the user has the alert preference enabled in settings (default). We also enable the network activity spin-wheel while the request is being processed, so users get UI feedback for the start of the request, the processing of the request, and the completion of the request.