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>
Remove most exceptions from getNode() (and variants)
Fix warnings and other misc. minor changes
Fix NoisePerlin3DEased return value