spearmint: Use Xbox 360 like virtual gamepad like SDL2

Expose low-level access to joystick axis/button/hat events to cgame.
Virtual keys for executing binds are included with joystick events.
Move in_joystickUseAnalog to cgame.

Currently joystick vitrual gamepad remap is hard coded to Ouya controller
for Linux. >.>
spearmint: Allow remapping joystick events to virtual keys

Replace hard coded Ouya remap with a joystick event remap system.
spearmint: Auto save and load joystick remaps

Saved in the top-level home directory, shared between all games and mods.
spearmint: Make joystick remaps be per-device type

Before they were separate for each player and each device type.
Only requires setup once per-device this way. It is less flexable,
but it covers the intended use (map to virtual gamepad keys, not
map to keyboard).

Currently devices are separated by name. sdl2 branch will use
a GUID from SDL 2.
spearmint: Prepare for setting up joy remap via SDL2
spearmint: Don't allow multiple players to use the same joystick

Results in duplicate events in UI, which is really confusing.
spearmint: Allow cgame to get and set joystick event -> key remaps
spearmint: Add name for annoyous union in joyevent_t

LCC complains. cg_public.h is _suppose_ to be the same between engine and game code,
so change it in engine too.
spearmint: Move getting keys for current joy events into cgame
spearmint: Remove unused cvars [ 234]in_joystickDebug