Basic Support for Python 3 (#827)

* Rudimentary python3 support

* update docs and trigger Travis

* fix some of the tests

* fix all python3 errors

* change env calls to just python

* add @python_2_unicode_compatible decorator to models for python2 compatibility

* switch netbox.configuration to from netbox import configuration

.travis.yml

@@ -9,6 +9,9 @@ env:
 language: python
 python:
   - "2.7"
+  - "3.4"
+  - "3.5"
+  - "3.6"
 install:
   - pip install -r requirements.txt
   - pip install pep8