Use Redmine API instead of mail handler. Refs #1560

- Failed automatic requests and assistance requests now
  use Redmine API for creating issues.
- ID's of the created issues are stored in toshokan:
    - Failed automatic requests store them on order events
    - Assistance requests store them on themselves.
- Sending book suggestions to separate mail. Refs #1559
Changes to assistance requests. Refs #1560
Save to Mendeley option on show page. Refs #1527

- Simple solution to just use javascript from the Mendeley bookmarklet
  on a link. This then opens the Mendeley importer with options for
  tagging etc.
Fix a font bug in the footer.