Jatris - Working on bgm code

In these last days I have been working on Jatris audio subsystem.
The bgm code was not working so it had to be recoded, now it seems to
work (remain only some funny behavior).


No bgm will be included in Jatris for the moment, but the game will search for
a bgm.mp3 file under the folder jatris on the sdcard and play it if found (and
music is enabled on the options page), so you can the music you prefer as Jatris
bachgroud.


Also found (and solved) a graphic glitch in hint subsystem for non native resolutions.


Hope to release a new update soon.