#296 Checkboxes in Breakpoints Panel

[Mathias Ricken]

Instead of displaying "enabled" or "disabled" and using
the "Enable"/"Disable" button, breakpoints in the
Breakpoints Panel should be enabled or disabled using
checkboxes directly in the tree.

For an example, see

http://www.objects.com.au:8088/objects/java/examples/swing/CheckBoxTreeLeaf.do