Add 'order' method to query.

Manually apply diff from Tagtoo-master:

    5f796e66a189fe1cef466cdffe23896358b78dc9^..
    4a772c709fda1420a36e42bd0c90a0bb2fc791c5
Add coverage for Query.order().

Fix bug uncovered by those tests.
Neaten docstring.
Add cursor handling to datastore.query.Query.

Manually apply diff from Tagtoo-master:

    25672e10fc359c67e0d267db2f23928b0a5761ca^..
    90ac07db1bcd3ebfd89f43ee9b59ded1cd8dd643

Add unit test, fix bugs.
Fix typo.

Incoporate feedback from @dhermes.
Rationalize docstring.

Incorporate feedback from @dhermes.
Resolving all sphinx warnings and parse errors.
Fixing remaining PEP8 long line issues.
Merge pull request #203 from tseaver/feature-datastore_query_order

Feature: datastore query order
Merge pull request #206 from dhermes/tox-docstring-fix

Sphinx and PEP8 docstring fix
Resolve conflict with master after 'order' feature landed.
Merge pull request #204 from tseaver/feature-datastore_query_cursor

Add cursor handling to datastore.query.Query.
Making all generic gcloud/ files PEP8 and pylint compliant.