Mesh iterators (me.faces, me.edges, me.verts, face and edge iterator) store the iterator progress in the python object.

This made nested loops with the same python object mess up.
eg-
faces= me.faces
for f1 in faces:
  for f2 in faces:
    print f1.index,f2.index

This didnt work, fixed by initializing the iter value at -1, so any greater value will create a new BPyObject with its own iter value.
once iteration is finished, its set back to -1.

Also made face and edges iter value a char instead of an int to save some memory.

source/blender/python/api2_2x/Mesh.h

@@ -89,7 +89,7 @@ typedef struct {
 	PyObject_VAR_HEAD	/* required python macro   */
 	Mesh *mesh;			/* points to a Mesh */
 	int index;
-	int iter;
+	char iter;			/* char because it can only ever be between -1 and 2 */
 } BPy_MEdge;			/* a Mesh edge */
 
 typedef struct {
@@ -102,7 +102,7 @@ typedef struct {
 	PyObject_VAR_HEAD	/* required python macro   */
 	Mesh * mesh;
 	int index;
-	int iter;
+	char iter;			/* char because it can only ever be between -1 and 4 */
 } BPy_MFace;			/* a Mesh face */
 
 typedef struct {