Use new optional framed glasslike drawtype
Allow only boat driver to be detached from boat (fixes #276)
Add improved grass textures by @Philipbenr (slightly modified), fixes #323
Tweak some textures, new chest texture
Merge remote-tracking branch 'minetest_game/master'

Conflicts:
	mods/default/textures/default_apple.png
	mods/default/textures/default_chest_front.png
	mods/default/textures/default_chest_lock.png
	mods/default/textures/default_chest_side.png
	mods/default/textures/default_chest_top.png
	mods/default/textures/default_desert_stone_brick.png
	mods/default/textures/default_snowball.png
	mods/default/textures/heart.png