Remove authority preview from /select_authority

Clicking a search result now takes the user directly to the authority
show page.

Removes the step numbers from the headers as the show page interrupts
the flow and seems pointless to add workarounds in public_body/show just
for this.
Tidy up request/select_authority.html.erb

- Align indentation
- Use named path for form url
- Use %Q() to avoid string escaping
- Use :anchor option to link to help page section
- Use symbols for form tag names
Improve /select_authority search box

- Make it wider
- Add a placeholder
- Translate placeholder and title text
Move “Can’t find an authority” to sidebar

Move the “Can’t find an authority” actions on the
/select_authority page to the right of the search
results
Add some specs to MailBackend
Add fix for Apple Mail with attachments
Add margin to bottom of admin views

Prevents the pagination being squashed up against the window edge
Redirect /help to /help/about

Shouldn't really 404 on an important/accessible URL
Use mysociety's version of ruby-msg.

A temporary measure until https://github.com/aquasync/ruby-msg/pull/10
can be merged. ruby-msg and sass (>=3.3) both define their own versions
of OrderedHash (sass only uses its version under Ruby 1.8.7) and they
conflict.
Upgrade compass-rails to version 2.0.0

2.0.1 depends on sass 3.3.13 (as described here), which causes segfaults
under ruby 1.8.7 on asset precompilation.
Merge branch 'help_page_redirect' into rails-3-develop
Merge branch 'issues/1437-apple-mail-attachment-parsing' into rails-3-develop
Merge branch '1663-split-select-authority-page' into rails-3-develop
Merge branch 'update-compass-rails-conservatively' into rails-3-develop
Merge branch 'rails-3-develop' of ssh://git.mysociety.org/data/git/public/alaveteli into rails-3-develop
Merge branch '1433-admin-bottom-margin' into rails-3-develop
Revert text changes in 8a21f27

Further work on redesigning the request process [1] will reword these
lines, so don't make the translators do work for no gain.

[1] https://github.com/mysociety/alaveteli/issues/1526
Revert text changes in bf31b10

Further work on redesigning the request process [1] will reword these
lines, so don't make the translators do work for no gain.

[1] https://github.com/mysociety/alaveteli/issues/1526
Fix missing translation introduced in 962357c

962357c tidied the translation but left the translation call (`_()`)
around the variable rather than the string literal.
Upgrade to Rails 3.2.21

Provides fix for CVE-2014-7829.