Merge pull request #495 from fr1zle/master

Checking for isDead() at a more reasonable location. 
Fixed shift-click and stacking problems with armor/tool

Signed-off-by: Irmo van den Berge <bergerkiller@gmail.com>
Fixed the snow placement bugs

Signed-off-by: Irmo van den Berge <bergerkiller@gmail.com>
Added damage values to entities. Added Wither potion effect.
Fixed the bugs caused by the snow placement fix

Signed-off-by: Irmo van den Berge <bergerkiller@gmail.com>
World generation improvements

Signed-off-by: Aleksi Sapon <QcTechs@gmail.com>
Prevent lightning strikes in snow
Snowfall when snowing
Merge pull request #496 from DDoSQc/master

World generation improvements
Burn baby burn, disco inferno! (Implemented fire ticks)
Added a cause to the fire damage.
More spread out snowfall