ENH: static test methods for matching simple cell shapes

- (tet, pyr, hex) can be identified from their number of faces
  and vertices. For these common shapes can use static `test()`
  method instead of the virtual isA() method.

  This is much cheaper for calling on an individual basis since
  it avoids the overhead of constructing an object.

ENH: tetCell edge/reverseEdge (already had tetEdge)