Remove dev_requirements.txt

Reasons:
- outdated packages (tests were failing)
- not tested (tox/travis-ci don't use this file)
- lots of unneeded packages for the project (ansible, gmp2, ...)
fix encoding issue on py3k during installation
Add tox configuration matrix
Add PyPi classifiers
Update .travis.yml to run tests with detox
test_plans_create: dict doesn't preserve order
Initial support for py3k
travis-ci: use travis matrix with tox envs
100% coverage for views.py
README: advise to use detox for tests
Remove redudant scripts for testing
coveralls: after_script -> after_success
Merge pull request #131 from iElectric/tox

Add Tox support, py3k support and improve test coverage