Fix values_list/values_dict

[willkg]

This fixes values_list() and values_dict() so that everything works the same in both ES 0.90 and 1.0.

Further it documents the details.

It also fixes some goofy stuff in the test harness.

Probably some other things.

r?

[willkg]

@mythmon Does this look sane?

[willkg]

The copious fields documentation is here:

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-request-fields.html

[willkg]

All the tests pass with Elasticsearch 0.90, 1.0.3 and 1.1.2.

[adngdb]

From my ElasticUtils-newbie point of view, this looks good!

[willkg]

Fixed that lame thing @AdrianGaudebert found.

Landed in:

03f4094 Fix S's values_list/dict re: ES 1.0