move bmesh array lookup data and utility functions from editmesh into bmesh,
since enough bmesh operations can also take advantage of direct index lookups on verts/edges/faces.

developers note:
- EDBM_index_arrays_init/ensure/free -> BM_mesh_elem_table_ensure/init/free
- EDBM_vert/edge/face_at_index -> BM_vert/edge/face_at_index
- EDBM_uv_element_map_create/free -> BM_uv_element_map_create/free
- ED_uv_element_get -> BM_uv_element_get


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk@60959 954f8c5b-7b00-dc11-b283-0030488c597c