Merge pull request #28 from APSL/master

modified utils.py in order to work properly with python2 and python3
make registration API browsable
make all endpoints browsable
add FAQ section in docs
add old_password field in PasswordChangeSerializer, disabled by default
Merge pull request #30 from Tivix/develop

Develop
version 0.3.1
update demo requirements
fix bug in PasswordChangeSerializer
add missed requirement in setup.py