Update uservoice tab to new colours

Now I've been fiddling with the styling - I have a new set of colours to
use that better suits the scheme.
Fiddling with styling

Trying to get bootstrap overrides to work - doesn't work with bootstrap-sass.
Going back to using direct css overrides
I've got bigger fish to fry.

Also add some boostrap js hacks that willl auto add a boostrap-style error
style to a rails-style error classed object (ie field_with_errors will cause
the surrounding div to get "has-errors" on it)
Update devise views and error panel

now boostraperrific
Errors should be alert not notice

these are things that went wrong - so they should be displayed as an alter,
rather than a notice.
Add validation of name to a venue

Just so we had something to test view-validation-logic with.