Nicify results for more Python types

[willkg]

• 'T'/'F' (shows up in facet counts) get converted to True/False
• '2013-05-20T15:55:11' things get converted to Python datetimes

This covers issue #72 and also fixes a backwards compatibility issue because pyes converted datetimes for us.

feedback?

[willkg]

Thank you for the thoughts! I'm going to twiddle with this a bit and then submit changes.

[willkg]

@robhudson ^^^ That covers all the things you mentioned, plus it slims the scope of things down a bit and makes it overrideable.

r?

[robhudson]

Looks nice.

[willkg]

Landed in master: 90cfcde Fix backwards compatibility issue with ES results