add django 1.8 to travis configuration
add django 1.8 to travis configuration

trevoriancox/django-shibboleth-remoteuser,Brown-University-Library/django-shibboleth-remoteuser,uchicago-library/django-shibboleth-remoteuser,trevoriancox/django-shibboleth-remoteuser,uchicago-library/django-shibboleth-remoteuser,Brown-University-Library/django-shibboleth-remoteuser