Added feature to retain column widths upon changing the table model.
Improved the cursor overview:

- replaced the labels with a table for easier viewing;
- restored the double-click-to-jump functionality.
Updated the Unit-API to a more friendlier API:

- add a Value class to unify a Unit with a concrete value, allows
  easier API usage.
Several improvements:

- generic concept of Radix to display state values can also be used
  to display group summary values;
- updated to new Unit-API;
- some improvements and bugfixes.
Fixed a bug in the sample collecting algorithm:

- the timestamps of the state transitions were incorrectly
  determined;
- added unit test to verify the correct behaviour.
Added demo generator for testing short captures.
Some zooming issues fixed:

- time line view was not correctly updated in its width when
  zooming in/out causing it to not scroll synchronously with
  the main waveform view;
- zoom actions no longer update their own state (as exception)
  but instead leave this up to the zoom controller.
Fixed a zooming issue:

- when the WaveformView component is resized, we need to repaint
  it explicitly to ensure its view is consistent.
Fixed an issue with the data builder:

- when the last seen timestamp does not match the absolute length
  do add a new sample with the absolute length instead.