With this enabled (the default), saving a file will copy the main pane
value to the diff pane. This means you can see what changes you are
making prior to a save and also can undo changes in diff pane to see
save points and how they differ to the main pane.
indentSize now has intval applied so we don't end up with blanks, get 0
instead
bug file paths, timer and max line settings now saved, paths as array
and other two as int's
Saved at the end of the settings chunk
Also passed to useNewSettings function, so we can restart timer on
change (to do!)
