Save previously generated blocks on Mapgen blitback
Update Mapgen VoxelManipulator on buffer invalidation
Add LuaVoxelManip methods: get_node_at() and set_node_at()
Add liquid thread
Don't save alpha channel in screenshots (fixes #1451)
Merge remote-tracking branch 'minetest/master'

Conflicts:
	src/environment.cpp
	src/map.cpp
Change screenshot colorformat properly
Merge remote-tracking branch 'minetest/master'
use blank.png for unknown items
get block try
no liquid queue double lock
use more getBlockNoCreateNoEx with try
Dont crash on m_blocks_sent
Try to fix gcc46 build
Fix gcc46 #2
fix gcc46 #3
update games/default
Block flicker fix
Crash fix 1
Crash fix 2 (very ugly)