Finishes up content locking
 - hide more columns when a page is locked
Adds confirmation on the siteprefs dialog
moves locking prefs under content editing section of siteprefs.


git-svn-id: http://svn.cmsmadesimple.org/svn/cmsmadesimple@8839 3d254a34-79dc-0310-9e5f-be208747d8a0