upgrade rails to 3.2.17

Have had to upgrade CarrierWave from 0.6.2 to 0.10.0 as well as the
older versions appear to no longer be available. Gems that would cause
a problem if newer versions were installed have been frozen.

All the tests are passing, but CarrierWave is causing a deprecation warning:

DEPRECATION WARNING: CarrierWave::MimeTypes is deprecated and will be removed
in the future, get the content_type from the SanitizedFile object directly.
(will be removed from version 0.11.0)
Introducing separation of cron emails
Provisioning script for Vagrant box
Replace .rvmrc with .ruby-version
Update Rails to 3.2.18
Allow response to vexatious requests to be submitted without response input

Silently replaces the blank public_part field with the text
"Rejected as vexatious" to preserve the expected data structure.
Keeps the submitted response if the responder has provided one.
Remove delete option from admin forms
Route "Respond" link to request_path as per the Request title link

Also removes new_response_request_path route as it's no longer used
Change button text to "Submit Response"
Prevent response being submitted with request state of New
Remove ability for admins to set status when creating requests
Stop settled requests showing as overdue
Fix bug in email address validation