geospatial validations
Fixes pull299
PR:299. Complete documentation
Merge remote-tracking branch 'upstream/master' into develop
Merge branch 'develop' into geospatial_validations

Conflicts:
	eve/io/mongo/validation.py
merge
Merge remote-tracking branch 'upstream/develop' into develop
Merge branch 'develop' into geospatial_validations

Conflicts:
	docs/features.rst
Merge branch 'geospatial_validations' of github.com:jlmadurga/eve into jlmadurga-geospatial_validations
Merge remote-tracking branch 'upstream/develop' into geospatial_validations
PR_299:rename eve.io.mongo.utils to eve.io.mongo.geo
Merge branch 'geospatial_validations' of github.com:jlmadurga/eve into jlmadurga-geospatial_validations
XML nodes are ordered. Closes #441.
Python 2.6 doesn't support OrderedDict from stdlib

So I had to add support for the back-port version. Addresses #441.
New test also runs with Python 3. Addresses #441.
Make concurrency checking optional during get_document()
Item _internal functions
Kevin Funk
Comma delimited sort syntax.

You can now use something like ?sort=lastname,-age as an alternative to
MongoDB syntax.

Closes #443. It takes a slightly different approach than the original PR
though, as the changes are all introduced at the Mongo data layer level. This
allows future data layers to parse the sort syntax as desired.
tox positional arguments