rna/python api change: rename Mesh.faces --> tessfaces, since existing scripts are using this to modify the mesh and its confusing that the edits are not kept.

This also makes it clearer that the faces are for tessellated results only.

Added a section on the Gotcha's about upgrading scripts, the pros and cons of MeshTessFace/MeshPoly/BMFace.
and spesifically how to upgrade importers and exporters for 2.63+.

doc/python_api/sphinx_doc_gen.py

@@ -270,6 +270,9 @@ else:
     import fnmatch
     m = None
     EXCLUDE_MODULES = tuple([m for m in EXCLUDE_MODULES if not fnmatch.fnmatchcase(m, ARGS.partial)])
+
+    EXCLUDE_INFO_DOCS = (not fnmatch.fnmatchcase("info", ARGS.partial))
+
     del m
     del fnmatch