libuEv v2.1.3

Changes

• Update joystick example, use first device, /dev/input/js0
• Minor refactor of uev_exit(), use _SAFE macros to traverse list of watchers instead of while()
• New API test to verify that uev_exit() terminates properly
• Make uev_signal_stop() idempotent

Fixes

• Let uev_timer_stop() call close() on the timerfd directly, do not call uev_timer_set() since that may cause lockups or hangs