Serving mode

This work includes:

- pushing to the vendor map after login
- allowing the vendor to set their location by dragging and zooming the map
- allowing the vendor to go into "Serving Mode"
- super sweet animation to assure the vendor they are in Serving Mode :)
consider making the image a class variable and setting it in the `init()` method and then using it here. Creating images are expensive so this would help performance.