Narrow the scope to load fewer objects

I believe this could load HostPath hashes for HostPaths on other sites, not
just the relevant one. It wouldn't have updated the Hits on those sites as
the Hits are scoped to the relevant site.
More efficiently update the related hits

Rather than fetching and instantiating each Hit that should be related to this
mapping, just send a single SQL UPDATE to update them all.
Update HostPaths, not just hits on Mapping create
Delete http_status columns from mappings tables
Prevent PhantomJS auto install

* Upgrade jasmine to 2.0.2
* Use new config.prevent_phantom_js_auto_install option to avoid
security errors
Merge pull request #289 from alphagov/stop-phantomjs-download

Prevent PhantomJS auto install
Remove (nearly) all traces of http_status

...except for in the versions helpers, which can be tidied up once
we have rewritten history so that all existing versions only refer
to type and not http_status any more.
Use new govuk_admin_template gem
Apply govuk_admin_template to transition

* Delete styles now coming from gem
  * Put back some styles not appropriate for gem
* Setup content blocks for main template
* Remove bootstrap from gemfile
Put back tag styles

* Remove from base and put into separate stylesheet
Use javascript framework from admin gem

* Delete modules and framework files and specs that have been moved to
gem
* Rename GOVUK to GOVUKAdmin for existing modules
* Leave non-modules as GOVUK for now
Include libraries within jasmine tests

* Specify compiled gem javascript file so that bootstrap and jquery,
along with framework are available for tests
Increase specificity of tag delete icon in input

* Override select2 styles with greater specificity
* The admin gem refactor had changed source order, and added
specificity was necessary to keep the little close icon blue
Add gem style guide to transition
Merge pull request #288 from alphagov/with-admin-gem

Switch to using govuk_admin_template
Fix error when paging past end of hits

Someone might do this if they are guessing at the page numbers as a way of
navigating through a large list.
Merge pull request #290 from alphagov/delete_http_status_columns

Delete http_status columns from mappings tables
Bump Rails to 3.2.18, to get the latest security updates
Move existing specs for View models

* were in a flat structure, needed to correspond to hits/mappings
Add a View::Mappings::Filter

* A starting point for getting too many fields out of MappingsController
* Encapsulates filtering and sorting, takes params and produces a
  mappings collection