Remove API from player.lua

It's now in game_api.txt
Fix xpanes API
Enable dungeons by default
Clean up treegen code
Fix dye stuff, fixes #243
Use new firelike drawtype
Some new textures (natural beauty texturepack)
Make new textures fit existing style
Merge remote-tracking branch 'minetest_game/master'

Conflicts:
	mods/default/functions.lua
	mods/default/textures/default_cobble.png
	mods/default/textures/default_dirt.png
	mods/default/textures/default_furnace_bottom.png
	mods/default/textures/default_furnace_front.png
	mods/default/textures/default_furnace_side.png
	mods/default/textures/default_furnace_top.png
	mods/default/textures/default_grass.png
	mods/default/textures/default_grass_footsteps.png
	mods/default/textures/default_grass_side.png
	mods/default/textures/default_mossycobble.png