beta 7 WIP a

added chapter select for chapter 6
changed all guard to provide 30 flak instead of 10
fixes #52
fixed a crash with displaying missiles with new renpy version. flak icon
now gets displayed properly.
using stealth removes the red tile colourings
Merge remote-tracking branch 'origin/master'

Conflicts:
	classes.rpy
Introduction of battle log
Filters for battle log