An unusual big commit, unfortunately needed because none of these changes would make sense nor work individual. A quick list of what have been done follows.
* Introduced a control panel to control buttons replacing the FAB bar
* `ConfigurableButton` and `OnScreenConfiguration` interfaces have been introduced to allow for easier proxying of actions when applying the same changes to all buttons
* Button resize logic has been stripped from the buttons in favor of the new sliders
* General cleanup and renaming of various methods to better reflect their functionality
Edit mode configuration parameters are now shared between the view and the buttons in a small `OnScreenEditInfo` object, avoiding variable duplication about edit state. The `editingTouchHandler` has also been simplified to only lookup the button if one wasn't being edited already.
* Add bold text and antialiasing for osc buttons
* Fix osc dpad and button position (widder than taller)
* Set default OSC color to white background with black text
`PreferenceSettings` was removed in favor of:
* `AppSettings`: stores general purpose settings mostly used for UI configuration and state
* `EmulationSettings`: stores emulation-related settings, most of these are passed to native emulation code
SharedPreferences will be partially swapped out in the future to support per-game settings. In the meantime, make it clear from which class settings are coming from.
