Store/restore pref values for drop_stone_mode, bottomsac, decosac

[Gaetan Bisson]

[2014-07-16 22:09:15 -0700] Dirk Hohndel:
> You are storing the values in preferences - but you need to add code to
> store those values on disk (via QSettings).

But they are already stored on disk:

	$ diff Subsurface.conf.orig Subsurface.conf
	161a162,164
	> drop_stone_mode=true
	> bottomsac=12000
	> decosac=15000

-- 
Gaetan