django 1.7 compatibility

fixes python 3.2 compat

apply some pep8 rules

django 1.7 compatibility

fixes django 1.7 compatibility

removes DBNAME env var and force db name to 'concurrency'

travis: exclude mysql with python 3.x

travis: exclude all mysql with python 3.x

django 1.7 plugged application's model handling

code clean and fixes documentation

new travis config. use tox as matrix

new travis config

fixes travis config

updates demo requirements