BUG: Fixing Crash due to Widget destruction

Changed the connection type from Queued to Direct when editing is completed w/r to both unit and non-unit line edit widgets.

The issue was that a queued connection may be processed after the widget that caused the signal to be fired is deleted.

Also corrected an issue when resetting an item's value back to its default when the item's units are unknown to the units system. In this case the widget must only be giving the default value string without the units attached.