This apparently has fallout: the PS4 (and maybe PS3?) controllers apparently
report some bogus axes, but it won't change the axes we currently expect, and
thus the game controller config string is still stable.
Fixes Bugzilla #2719.
Since all device detection/removal happens on the main thread now, post events inline with when the status changes occur.
Also fixed rare cases when joystick API functions could return data about removed joysticks when called with a device index.
An existing hint lets apps that don't need the timer resolution changed avoid
this, to save battery, etc, but this fixes several problems in timing, audio
callbacks not firing fast enough, etc.
Fixes Bugzilla #2944.
Ryan C. Gordon
Sam Lantinga
Philipp Wiesemann