Fall damage adjustments

Changed distance before damage, added a fix for fall damage when
jumping.
Fixed spawnpoint storage

Spawnpoint were off by a block when being stored, found the cause and
fixed it.
More spawnpoint fixes
Another bugfix
Fixed friction crash

Fixed a crash while calculating friction if the player was on a block at
the right edge of the screen.
Fixed previous commit

Somehow managed to not include the friction patch in the previous
commit. Here it is.
Cleaning and Fixing

Cleaned up the lighting code and fixed a bug that I found. (line 126 in
Block.pde). When a lamp was under water but not under a solid block, it
would not light the blocks below it. This was because the code that was
controlling it was in an else if instead of an if.
Another fix
Fixed respawn collision

Fixed an issue where the respawn block wasn't detecting player
collision.
Fixed NullPointerException

Game was crashing due to a typo in BlockSpawnpoint->type.