if blender freed the BMesh before python was finished (on exit editmode for eg), python would attempt to access the bmesh to clear python pointers in it.
added some missing functions too - which are not used yep but should be there for api completeness.
* CDDM_set_mloop
* CDDM_set_mpoly
* BLI_mempool_count
On a place, Ctrl+T, Fkey would create a quad overlapping the 2 Tris.
Now this case is checked for in a general way - if the bounds of the face are already filled in with faces (that _only_ use these edges-verts), then dont create the face.
This is an option for the 'edgenet_fill' operator, since creating the face isnt incorrect, just not-what-you-want mostly.
added functions
* BM_edge_share_vert - returns shared vert between 2 edges.
* BM_face_exists_multi, BM_face_exists_multi_edge - check if existing faces fill the edge bounds.
* also add BM_ELEM_INTERNAL_TAG so low level functions can tag without conflicting with higher level functions that also rely on tagging elements.
* better type safety for BM_elem_flag_* and BM_elem_index_* functions.
* add BMElem type to be used where BMFace/Edge/Vert/Loop can be interchanged.
* fix bug in select manifold, found when making functions more strict.
* BMFace.copy_from_face_interp(face)
* BMLoop.copy_from_face_interp(face, vert=True, multires=True)
These are important for rebuilding geometry from existing faces without loosing UV's, vcols etc.
* remove 'select' and 'hide' from BMLoop
* remove BMesh.update
* add BMesh.normal_update(skip_hidden=False)
* add BMElemSet.index_update(), eg: bm.verts.index_update()
bmesh api
* BM_mesh_normals_update() now takes skip_hidden as an argument
(previously this was default behavior), however this isnt good when
using BMesh modifiers, where you want all normals to be recalculated.
* add bm_iter_itype_htype_map[], to get the iter type from a BMesh
iterator.
bmesh.utils.face_join(faces)
added a utility function for converting a list of python BMesh elements into a C array.
use for this face_join as well as BMesh.faces.new()
* bmesh.types, just allows access to BMVert, BMEdge etc.
* bmesh.utils, so far only added edge_split() function, this module will give access to mesh editing functions.
* Only have 1 python object per bmesh, vertex, edge, loop, face.
* Store pointers back to the python data in a custom data layer so as not to use more memory for normal editing operations (when pythons not running).
* Currently this data is created and freed along with the BMesh PyObject.
* Incidentally - this fixes comparisons for bmesh elements which wasnt working before.
