BUG: pickle failing on FrozenList, when using MultiIndex (GH4788)

INT: add __reduce__ to FrozenList for pickle support

INT: add 32-bit 2.7/3.2 pickles

INT: add AMD64 0.12.0 pickle

TST: add round-trip test for current version

INT: remove 0.13 testing
Merge pull request #4791 from jreback/pickle_fix

BUG: pickle failing on FrozenList, when using MultiIndex (GH4788)