Yet more fixing for the Firefox jumping toolbar problem...

See #282
Docs updates
Fix problem with import button triggering checkbox on Firefox

It seems that there is a broader problem with the way that the button
is embedded within the label of a checkbox; even on Chrome it meant
that the checkbox active state was triggered when clicking on any of
the buttons. The user experience was in any case confusing; it wasn’t
obvious that clicking on the label to the right of the button would
flick the checkbox.

The solution takes the buttons and labels out of the checkbox label.
Preserve modified title when reusing drafts

Should fix the problem raised by @xcazin
Generate new tiddler titles that aren't already subject of a draft