new sura and aya playing support

[Ali Gholami Rudi]

Hi all:

I've added ``gtk.play_sura`` and ``gtk.play_aya``. For instance::

[gtk]
play_aya = mplayer -noconsolecontrols /path/to/folder/${sura}${aya}.mp3

``${sura}`` and ``${aya}`` are replaced with zero filled sura and aya
number.

You can also ask noor to follow ayas; that is when the player finishes
with zero return value noor goes to the next aya. For this to work
you need to set the ``gtk.follow_ayas`` option::

[gtk]
follow_ayas = 1

You might also consider ``gtk.shadow_ayas`` which will highlight the
current aya; it can be useful when using ``gtk.play_aya``.

Also you can stop the player with ``K`` key.

Regards,
Ali