Moved .up() and .down() methods from Modifier API to Modifier sequence
API (also renamed them to moveUp() and moveDown() ). Locating methods
which modify the "parent" structure in objects didn't seem consistent.
All settings through Blender.Modifier.Settings
see the epydocs
Also added some error checking to fix some possible segfaults.
Added more epydocs
Modifiers API should be stable enough to use now, though give it a bit of time for testing.
More Modifier API changes:
* add Blender.Modifier.Settings dict with constants for modifier types
* add mod.type attribute, which returns type of the Modifier
* add some internal consistency checks in ModSeq_remove