Fixed the battle tutorial script.
Fixed some credits (long time due :/)
Fixed the center -> forest entrance map transition event.
Prevented the map mode from complaining when the default music file is empty.
Simplified the screen fader and corresponding image draw code.

It now only uses an overlay
instead of applying the fading colour
on each and every images on the screen.

This should be quicker and saner and fixes applying fades above
particle effects.