Rom

[fixed] Fix for bug where patterns could match primary key values in prefix
or suffix indexes. Thanks to github user https://github.com/peter-conalgo
for the bug report.

[fixed] Fixes SaferDateTime column.

[fixed] Travis CI - Python 2.6 is no longer supported in Travis (even if it is
supported by rom :P)

[fixed] Added more tests, removed pk as included by default in select()

[added] Model.query.select(...) allows for selecting individual columns from
the model, and will return (by default) a dictionary, but can be prodded
to produce a namedtuple (or anything you want). Thanks to github user
https://github.com/peter-conalgo for the feature request
[added] columns.SaferDateTime() to offer better type checking of values set to
datetime columns (partly the result of the in-Redis representation of the
column data)

[fixed] If the first method that was called on the rom.session object was
either .refresh() or .refresh_all(), rom would raise an AttributeError.
Thanks to Github user https://github.com/peter-conalgo for the bug report.