Wielded fixes. Add shaders support.
Add Generator Element Management framework

Add BiomeManager, OreManager, DecorationManager, and SchematicManager
Add eased 3d point-value noise functions
Mapgen v7: Fix uninitialized spflags
Mapgen v5: Fix minor style issue
Fix compilation under some Linux distributions
Add option 'eased' to NoiseParams

Signed-off-by: Craig Robbins <kde.psych@gmail.com>
Improved VoxelArea variable locality, thus performance

Signed-off-by: Craig Robbins <kde.psych@gmail.com>
Merge remote-tracking branch 'minetest/master'

Conflicts:
	src/emerge.h
	src/mg_biome.cpp
	src/mg_biome.h
	src/noise.h
Merge commit '92815ad'

Conflicts:
	src/noise.h
Merge remote-tracking branch 'origin/master'