Default result backend should be "amqp"

Also, fix the broken blank postcard generator.
Add Favorites feature
Hide toggle favorites links when not authenticated
Require latest django security update
Fix bug with excluding words from search
Add tests for user search
Tighten up requirements
Add travis-ci configuration
Add venv to gitignore
Fix install script targets
Re-organize travis.yml
Make failing tests exit with non-zero
Add diagnostics for selenium firefox path
Explicitly set directory for installer's tar cmds
Clean settings; fix for current firefox/selenium
Remove travis

Building with live selenium tests is too slow for travis. Until we have
a faster integration test option, best just run tests locally rather
than tie up travis only to fail with timeout.
Filter pending scan users to org
merge requirements
Filter scan split and doc author selection to org
Merge branch 'master' of /git/btbv2