Documenting the fact the more_results is unfit for use in datastore.
Merge pull request #287 from dhermes/document-more-results-failure

Documenting the fact the more_results is unfit for use in datastore.
Moving encrypted key to regression subdirectory.
Merge pull request #286 from dhermes/move-encrypted-key

Moving encrypted key to regression subdirectory.
Implements group_by, projection and offset on datastore Query.

In addition, __eq__ was implemented on datastore.key.Key
to allow for easy comparison.
Addressing corner cases for datastore.Key.__eq__.

These corners are a direct result of #274.
Remove notes about datetime.date objects and timezone matching.

Issues #278 and #279 have been filed to address.
Document regression tests, make run_regression fail if environ not set.
Adding support for queries in regression test.

This is an attempt port the gcloud-node regression tests
for queries over to gcloud-python.
Makes entities for query tests persist to avoid flakiness.

This came about from conversations with @silvolu and
@pcostell. Unfortunately, even if an entity has been stored
and indexes built for 10+ minutes, the tests

- test_query_simple_filter
- test_query_multiple_filters

are still flaky.