1. Remove empty lines
2. Change double quotes to single quotes.
3. A minor optimisation in the history_log_event() api. Not to get the user id
   except when there is a change.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@1124 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9