Ticket searches with OlderDate/NewerDate restrictions are cancelled if OlderDate is before NewerDate or if NewerDate is in the future.
Since those kinds of searches would create empty results regardless of other restrictions, cancelling the searches speeds up the response.
This fixes bug #3434.
Fixed bug#7885 - Links of 'merged' tickets are not displayed with a 'line-through'.
Add use strict and use warnings to generated new file.
Improved frontend tests.
Merge branch 'master' of git.otrs.com:otrs/otrs
SMTPTLS backend no longer requires username and password.

Some (local) SMTP servers do not require the username and password but
still use TLS.
Fixes bug#6985 - http://bugs.otrs.org/show_bug.cgi?id=6985
Fixed bug#8667 - No error Message when tryiing to Merge Ticket with itself.
Fixed bug#5127 - Configurable listing of agent names in stead of hardcoded layout.
GroupUserRoleMemberList in HASH now returns Role Names or User Logins as values.

Fixes bug#7593 - http://bugs.otrs.org/show_bug.cgi?id=7593
Added unit tests.
Queue lists now show more than 51 tickets per page.

Previously each page displayed max. 51 tickets even if the agent
configured a higher number.
Fixes bug#5475 - http://bugs.otrs.org/show_bug.cgi?id=5475
Code cleanup
Removed unused LoopProtectionObject.
Re-added entry which was deleted by accident.