made -gamemode better, add Cobble Fence Post

in gamemode 0, starts off in inventory with 1 full stack of a lot of
block types, also, Cobble Fence Post in game inventory..
damage adjust, and can only fly in gamemode 0
Merge commit '79d4779cb6fdffb016eca76077a35c3b4485f374'

Conflicts:
	main.py