Merge pull request #14 from SerialVelocity/master

Fix most problems for Mac OSX. Only thing left is Samplers.
updated submodules
one more step to BraLa on mac, see glamour/issue#4
removed global _window
improved queue implementation
updated submodules, mac support in glamour
changed the order of tessellation loops
removed unhandled packet debugging message
improved memory-management debug output
changed block-layout in memory to blocks[x][z][y]
updated submodules
using new glwtf window properties
removed init_opengl function
updated glamour submodule (VAOs)
made chunk_removal_queue more dynamic
implemented world.initialize which creates the VAO
reverted VAO changes made to world
implemented VAOs
updated submodules, glamour.vao changed
const -> enum
make sure remove_all_chunks is called from the main-thread