LDEV-1613, LDEV-1611 Options to enable adding images/ inserting links now working. (The options control whether or not to show those buttons on the FCKeditor)
Fixed up code that creates the folder so that it only tries to create it when the folder doesn't exist - eitherwise it gives a false error when it tries to create the images folder for a second time.
LDEV-1571: Sync gates to open for group based and teacher chosen branching. The "potential list of learners" is restricted to the group of learners associated with the group assigned to the branch.
LDEV-1611 Added custom learner toolbarsSet for fckeditor with the addition of Image and Link buttons. The idea is to show/hide image/link buttons depending on preferences chosen for wiki in author at runtime.
