Fix appearance of external tools widget

1. Currently on external tool finish its whole output expands in external tool widget. When a few tools were run then it gets difficult to find something in the widget. It would be handy to keep output item collapsed by default.

2. If external tool puts long string to its log, then output widget increases its width without any limit. Some approach should be developed to keep relevant size of the widget.

3. The executing string for MACS tool doubles in the widget. It should be cut