Remove joystick code

This effectively removes joystick support from XBMC. This rids us of our
platform-specific, rampantly-duplicated and overly-complex joystick handling
spread across far too much of the codebase.

Joystick support will return in a subsequent commit. Platform specific code
is to be isolated entirely in binary add-ons.

Removal of joystick code is incomplete on Android (todo)
Remove joystick keymaps