TST: windows compat for testing / msgpack
- skipping a couple of parsing routines that cause odd test failures on windows
- msgpack compat for windows (not tested before, prob not working correctly). Slight internal API change where writing the `dtype.name` rather than `dtype.num`, but back-compat is ok on this. (and forward compat is better).
- skipping a buggy test for ujson on windows on 2.7 only
