Refactor out common error handling
Use error base to display accessible error message
Create hook for plug-ins
Fix tests
Merge pull request #1427 from opf/feature/4222_no_flash_message_on_status_page

[Fix] 7700 no flash message on status page
Revert "Fix whitespace in RFPDF plugin"

This reverts commit 29e89917fc8121818bf4ac001389573c37501d9e.
adapt Rails3 path of code.rake vendor