Django-ltree

- Add support for 2.7
- Tox tests
- 83% Code coverage
- Several fixes

Thanks to boryszef !

Completes setup.py setup and release

Current version supports essential ltree operations.

Contributions

- PostGIS backends should also suffice for ltree support 1 by bctcvai

TODO

- Documentation for existing operations
- More complete demo project
- Transplant branches from tree helper