inlet / outlet active zone for ui.* objets

[60-hz]

pd has recenlty enlarged the active i/o lets zone for a much better user experience. Ceammc ui objets should have the same behavior, and could benefit from the updated code.

Here it is:

pure-data@bbc2801

[60-hz]

Actually the resize to bottom function for UI could be only half...
While patching, users spend more time on connecting boxes rather then resizing, and small inlets are difficult to catch on big screen.