Buncha bugfixes [SEE DESC]

Fixed generation values not being written
Fixed piston being able to push water
Fixed ice creating a non-source block (still doesn't update though)
Removed problematic piston code
Alpha sorted PistonBreakable list
Merge remote-tracking branch 'upstream/master'

Conflicts:
	source/Piston.cpp

Merge conflict?
Okay, changed to xoft's partial fix
Generation and simulation defaults

...are no longer set, instead, the server operator is told to set them.
Merge pull request #91 from tigerw/master

Fixed piston being able to push water
Fixed ice creating a non-source block (still doesn't update though)