Token protect download/view actions.

This is as much a security risk as a weak password, since an attacker
has to know the mailbox/UID of the message. But doesn't hurt to protect.
Fix several XSS in delete forms.
Fix class name.
Throw NotFound exceptions.
Add ticket number.
Token-protect vbook form (Bug #12803).
[jan] SECURITY: Protect against CSRF attacks on share permissions form (Bug #12804).
Tweak
Sonar error: Unexpected token: ;, line: 391, col: 29
Update de translation.
Updated
Prepare releases.
Merge branch 'for_upstream' of git://github.com/sathieu/horde into sathieu-for_upstream
Prepare releases.
Use longer timeout for bugs.horde.org.
Released horde-5.1.5
Development mode for horde-5.1.6
Released imp-6.1.5
Development mode for imp-6.1.6
Released ingo-3.1.3