API CHANGE Removed LeftAndMain->BatchActionList(), no longer necessary as we're creating the batch actions form in the same class
ENHANCEMENT Changed CMSBatchAction logic to return JSON status changes rather than eval'ed JavaScript via FormResponse
ENHANCEMENT Ported batchactions in CMSMain_left.js to concrete javascript, and moved to new CMSMain.BatchActions.js file
ENHANCEMENT Using native CMSMain->BatchActionsForm() to render form instead of custom template markup in CMSMain_TreeTools.ss
git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/cms/trunk@92722 467b73ca-7a2a-4603-9d3b-597d59a354a9