Added note for disabling XSS filter method
Files/folders now draggable

LI tags now draggable
On drag, test if we are dragging with a key down. Also focuses CM editor
to show the cursor incase we want to drop into code and we'll then know
position
On drag end, perform a dropfile function
On drop, get mouseXY for area

Also now sets the area in top.ICEcoder.area, useful for other purposes
Dragging with key, drop file, paste URL functions

draggingWithKey is new param, to indicate which key we have down while
dragging, false if no key
pasteURL is new function to paste a URL into the editor. If CTRL/Cmd is
down, add the protocol and // as a prefix
draggingWithKeyTest - another new function, this will work out a key
that may be down whilst dragging, For now we set to CTRL (for CTRL/Cmd)
or false but could take other keys in future
dropFile is a final new function, when dropping a file, it will do
something. If we're in the editor area, paste the URL, if we're in the
files area, we'll move a file (a future update here). Finally, we set
mouseDown to false as we may have crossed from one area to another and
the event wouldn't trigger and flag not set otherwise
Also setting top.ICEcoder.area on mouse move, very useful so we can work
with that info (in the case of dropFile above)