Basic resource Gathering

1) HUD now contains attack and gather tiles.
2) Added /block type. Blocks represent persistent map features that
aren't turfs. Trees, furniture, walls, rocks, should all be built from
blocks.
3) Resources can now be gathered from Blocks.

There are several things missing from this system:
1) The player shouldn't be able to chop down all trees in no time at
all. Some sort of delay needs to be added to actions. This will require
an update to the whole action system.
2) Users shouldn't be able to chop down all trees for no reason.
Modifying the world will be a costly system, relying on some sort of
"character points" system. CP will be awarded over time or for doing
specific actions (combat?). Gathering will drain CP.