Fix mx.DateTime test
Fix pyflakes warnings (unused imports and vars)
Fix pyflakes warnings

Unused imports and redefinition of function
Add support for Solr's JSON API

For large results sets, this can be parsed and interpreted much more
efficiently than the equivalent XML response.

TODO:
 * Support JSON for queries other than /select
 * Support "interestingTerms" in MLT queries
More efficiency improvements for JSON client

The general principle here is that because the dicts json.loads gives us
are very close to the final format we want, we can just do a few
in-place modifications to these dicts rather than build entirely new
data structures.
Typo fix and comment
Merge pull request #77 from evansd/support_solr_json_api

Support Solr JSON api