Time64Cols don't work nicely with querying

[scopatz]

This is probably related to #119. See [1] for more details, but here is the meat of the problem (I think):

This is very likely a bug with respect to querying based off of Time64Cols not being converted to Float64s for the query itself. Under the covers, HDF5 and PyTables represent Time64 as a posix times, which are structs of two 4 byte ints [1]. These obviously have a very different memory layout than your standard float64. This is why this comparison is failing.

numexpr doesn't support the time64 datatype, nor does it support bit shift operators. This makes it difficult to impossible to use time64 columns properly from within a query right now.

1. http://sourceforge.net/mailarchive/message.php?msg_id=30726143

[avalentino]

This have been fixed by PR #232.