Added a burst generator.
Some cleanups and improvements:

- discovered that the SignalUI was always emitting *huge* polyline
  arrays, causing loads of memory to be used and needed;
- started working on improving the dockable views.
Added debug flag for testing purposes.
Added customized JTable variant:

- capable of exporting its contents to CSV or HTML.
Refactored the way annotations are used in tools:

- publish annotations through the ToolContext instead of a
  separate listener entity;
- make it easier to add annotations in tools by using a helper
  class;
- started work on showing annotations separately in a table in
  the main window.