Add button styles to admin request edit page

- Danger button for permenantly destroying request
- Primary button for saving changes
Emphasise the dangerous edit request actions
Add ttf-bitstream-vera to package lists.

Closes #618
Reword CTA copy on frontpage banner

In user testing no one clicked "Start Now" to make a request. All users clicked
"Make a Request" in the main nav, so lets try that here.
Add comma delimiters to request numbers on the front page

Originally implemented in 67a8be372ffcbe943ce33c2e55c9a560588ef6fe but lost over time.
Use each instead of for
Add visible_request_count to /version.json
Add confirmed_user_count to /version.json
Fix typo on /request/upload_response

This fixes a typo which cased the following to be displayed when
uploading a response:

    Respond to the FOI request 'FOI Request'FOI User

It now says (correctly):

    Respond to the FOI request 'FOI Request' made by FOI User

Thanks to Ben Fairless for the original implementation of this commit.
Update Gemfile.lock

Had issues similar to:

- https://github.com/bundler/bundler/issues/1375
- https://github.com/bundler/bundler/issues/1081

Was a problem with the Ubuntu packaged version of bundler. Seems to be resolved
in later versions of bundler.
Minor tidying of PublicBodyController#list

Spacing, parenthesis, etc
Support simple searching of bodies by short_name
Define track things constraint correctly

> The constraint fk_track_request_public_body on
> track_things_sent_emails is defined incorrectly, referring to user_id
> rather than public_body_id.

Via Robin Houston
Fix typo disable_constraints => constraint_disabling

This connection param is consulted in config/initializers/alaveteli.rb to see whether to load our patch for constraint disabling from lib/no_constraint_disabling.rb
Merge branch 'fix-install-typo' into rails-3-develop
Merge branch 'features/618-ttf-bitstream-vera' into rails-3-develop
Fix typo in password change email subject.
Merge branch 'issues/1460-search-body-by-shortname' into rails-3-develop
Merge branch 'issues/1510-upload-response-typo' into rails-3-develop
Rake task for cleaning up holding pen events