BUG: pytables minor changes
- ENH: moved Term to top-level panas namespace (like HDFStore)
- BUG: writing a Panel4D in cython (lib.pyx)
- BUG: interpreting axes paremeter to orient data
- BUG/ENH: allow appending of a different order of non_index_axes data 
  which then is ordered according to on-disk data
- DOC: explanation of how to orient data to provide optimal append/delete operations
- BUG/TST: more complete coverage of ndim and non-default axes ordering
- removed debugging memory calls
