opendingux: Update udev rule for gsensor

This updated rule ensures that the /dev/input/gsensor symlink will
always point to the /dev/input/eventX (created by evdev) and not
/dev/input/jsX (created by joydev). SDL1 can work with both, but SDL2
will only work with evdev.
opendingux: gsensor script: Wait for the node to appear before exiting

Otherwise a race might occur, when the application tries to access
/dev/input/gsensor before it is created by udev.