(tox) Implemented Tox

Added admin_extend/tests/ folder with sample test and settings file;
Updated .gitignore;
Added tox.ini file.
(tox) Integrated Tox

Added admin_extend/tests/ folder with sample test and settings file;
Updated .gitignore;
Added tox.ini file.
Merge branch 'tox' of ssh://github.com/pbs/django-admin-extend into tox
(tox) Some fixes

Added chagedir to tox commands and moved results xml file accordingly.
Merge pull request #3 from pbs/tox

Integrated Tox