Fixed some bad problems in the MIDI export, could ouput garbage or cr…

…ash the program.

Fix : minor ui glitch with pattern list

Export popup : fix automatic checkbox checking depending on the slide…

…rs clicked

Update themes

Fix selection size problem if paste width exceed song width

Minor graphical glitch : channel header on the right side sometimes needs the user to scroll a bit more to show up

Added feature list

Merge branch 'master' of https://github.com/stephanedamo/fmcomposer

Merge branch 'master' of https://github.com/stephanedamo/fmcomposer