Allow dev-like errors in production

For example for uniregtest. In the ENV, set
“DISPLAY_PRODUCTION_ERRORS=true”.
Add event age range. (Admin half.)
Better website title

It’s really confusing having multiple instance of the app open. This
makes the page title more relevant.
Add validation for event age range on sign-up
Attempt at: limit displayed event catagories to those allowed for registrants age
add styling to create a nice floating-bottom-banner
update todo, also delegate has_details and details_label through models, also display details_label on views
Fix: limit displayed event catagories to those allowed for registrants age
Enable travis
Fix tests
update todo
Merge remote-tracking branch 'scott/master'