Subsurface AppImage

[Willem Ferguson]

I run the AppImage on Ubuntu 15.04.
Only problem found till now is that preference settings normally reflect 
immediately in the dive display. E.g. if the gradient factors are 
changed, they normally reflect immediately on the dive profile. With the 
AppImage, the settings are saved but are only changed the next time 
Subsurface is launched.
I will do more testing of other features/tools.
Kind regards,
willem