Added a cursor builder & session provider:

- allows to define cursors in the same way as channels and groups;
- added support to directly get a styled label for a cursor;
- added concept of session & session provider to access the
  acquired data and annotation data.
In progress of refactoring the client:

- rewrite the way actions are handled in a more simple way;
- leverage the use of the OSGi service registry for many of
  the existing concepts, allowing a better separation of
  concerns;
- use EventAdmin for reporting status of Tasks;
- still many things to do.
Added session identifier to keep sessions apart.
Simplified user & window settings.
In progress of restoring the waveform view.
Added support for colors in channels & groups.
In progress of porting the old view functionality.
Added ClickableLink as generic component.
Made the new client completely independent of the old code.
Added some filename utilities.
Added a name property to a session; fixed a bug in cursor labelling.
Ported all tool-views and made those proper components.