[FIX]Allow posting comments when highlighter (codemirror) is on or switchable. Thanks Patrick Proulx for the fix. This will fix bug5294 in 12.x, but currently not reproducible yet in 13.x and trunk since http://dev.tiki.org/bug5316 (unsolved yet) seems to be interfering. 

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@53250 b456876b-0849-0410-b77d-98878d47e9d5