CLN: moved all data for tests to /data sub-dir of the tests
ENH: added legacy pickel generation/testing suppport

TST: added io/tests/test_pickle.py to test stored pickles
     added io/tests/generate_legacy_pickles.py to create legacy pickles
       on various arch and sytems (need contributions)
     added some sample pickles for 0.10.1/0.11.0
BLD: fix setup.py to load correctly data files
BUG: reading py2 pickles in py3 ok now
ENH: added py3 pickles, revsied to include SparseSeries/SparseDataFrame/Index/MultiIndex
Merge PR #3310