Made login view redirect already logged in users to dashboard.
Fixes #25
Merge branch 'tests-changes' into issue-25
Added test to check that wagtailadmin behaves correctly when LOGIN_URL is not set
Fixed issue with 'django.contrib.auth.views.login' not being reversed properly
Merge remote-tracking branch 'torchbox/master' into issue-25

Conflicts:
	runtests.py
Merge pull request #291 from kaedroho/issue-25

Made login view redirect already logged in users to dashboard.