fix input timer queue
if new timer has a timeout later than a timer in queue, the
new timer will be discarded and never be pushed into timer queue.
This is fixed by pushing new timer without timeout checking
and then sorting the queue according to timer timeouts.

This should fix #520 and #495.
add fallback_font option in G_reader_settings
Merge pull request #525 from chrox/master

fix input timer queue