Set up Bootstrap 3

This includes the bootstrap-sass gem and includes Bootstrap in 
application.scss, and includes a skeleton application layout.
Set up jquery-rails

This adds the jquery-rails gem and sets up a Javascript app manifest.
Restyle the best bets list

Move best bets into a table and show more information about each best 
bet in the list.

This also adds a confirm dialog before a best bet is deleted.
Add forms stylesheet

Added the forms stylesheet based on the existing one in specialist-
publisher.
Wrap form titles in header tags
Make the form submit button pretty
Reposition the application title in the navbar

There’s a -15px margin-left set by Bootstrap on the application title 
that is pushing the crown a bit too far too the left.

Resetting the margin-left isn’t so easy without building up a complex
selector, so I’ve offset the left padding by 15px to account for this.
Add styling for flash notices and alerts
Rename included stylesheets to include underscore

Nothing seemed broken before this change, but this seems like a thing in
specialist-publisher, so going to maintain the convention here.
Add validations to the BestBet model

Validate that:
- the query, link and user_id fields are present
- the match_type field is always either “exact” or “stemmed”
- the position field is a positive integer (or nil)
Use BestBet::MATCH_TYPES to provide select options
Tidy up controller and handle validation errors
Prevent ActionView wrapping fields with an error div

By default, ActionView wraps its own div around fields with errors. This
breaks the markup of the form builder (which wraps the field output in 
its own paragraph tags), so disable it and rely solely on the form 
builder for this behaviour.
Change alert messages in the controller
Merge pull request #7 from alphagov/make-pretty

Add validations and make pretty