Minor stability improvements in block emerge handling
L-systems treegen code tweaks.
Improved faces shading with and without shaders.
Fix issue #1275 - wielded index greater than inv size.
Merge commit 'cb3b42e' into merge3

Conflicts:
	client/shaders/nodes_shader/opengl_fragment.glsl
	client/shaders/water_surface_shader/opengl_fragment.glsl
	client/shaders/water_surface_shader/opengl_vertex.glsl
	src/map.cpp
	src/mapblock_mesh.cpp