Item11326: major speedups for reading large WebNotify topics. No functional changes (I hope)

git-svn-id: http://svn.foswiki.org/trunk@16448 0b4bb1d4-4e5a-0410-9cc4-b2b747904278
Item12316: correct redirect denied message

git-svn-id: http://svn.foswiki.org/trunk@16449 0b4bb1d4-4e5a-0410-9cc4-b2b747904278