Fixes a few minor bugs

Changelog:

 - fix: Mails sent from WebGUI now wrap at 78 characters, as the SMTP

   RFC asks, to fix problems with some SMTP servers when lines exceed 
   998 characters. (The Next Phase / MedIntellibase)
 - fix: Fatal Errors Kill Login Session
 - fix: Calendar Event recurrence stretching over daylight savings time changes use wrong times
 - fix: In IE, 'Insert WebGUI Image' loses some attributes
 - fix: Collaboration System threads sometimes unable to find next/previous thread