Item1910: error detection and correction when a manifest can't be found

git-svn-id: http://svn.foswiki.org/trunk/core@16586 0b4bb1d4-4e5a-0410-9cc4-b2b747904278
Item12417: simple optimisations including replacing \w with [a-zA-Z0-9_], and removing variables used as constants

git-svn-id: http://svn.foswiki.org/trunk/core@16587 0b4bb1d4-4e5a-0410-9cc4-b2b747904278