Google Summer of Code/2012/Improvements to Vespucci/Multi-API support

This should be pretty straight-forward, as the code is very clean. An additional preference will need to be created; changing the preference needs to reset the map data storage. If there are unsaved changes, the user needs to be warned that these will be lost. Passwords need to be saved per API, to allow the user to switch between different APIs without having to re-enter passwords.

Once there is a setting to select the preset for the easy editing mode, this should be per-API too.

A good improvement would be device rendering of the custom map data including the icons (done). A URL-scheme based interface to add APIs and presets could make this feature easier to use (done).