Custom watch attributes

[hwf1324]

Closed #6

This PR is currently in draft form and needs to be improved for accessibility to UI/UX.

Known Issues:

• The EditableListBox is not bound to a static text label.
• No changes to list items are reported when the list is manipulated via the Move Up/Move Down buttons.
• It can be tedious to translate watch attributes.

• The checkbox state is not binding to the watch attribute.
• Extra empty list items appear at the end of the list when the checkbox style of ListCtrl is enabled.

[cary-rowen]

Regarding the tab order: Could the list be set to receive focus before its associated action buttons? Usually, we want to access the list first, and then operate the related buttons.