ENH: Index(...) constructor creates a MultiIndex when appropriate.

- Series and DataFrame constructor autodetect when index/columns
should be MultiIndex
- prevents some seg faults in calls to cython funcs
- add tupleize_cols kwarg and update tests to git PR comments
- support name= xor names= in Index(tuples, ....) constructor
- docs

BUG: Index.identical(other) didn't compare type(other) to type(self)
DOC: updated dsinstro.rst