- fix empty log after changing log level
- improve performance of log widget even after long use (#35)
- add menu and config entry for setting a maximum log length
- fix log entries without specified color receiving the color from the
  previous entry
- improve non-GUI mode app support
- make it possible to show the mainwindow on top of other windows, by turning
  dialogs into top-level windows
- simplify Dialog instanciation and internal logic
- fix the "Calibrate" button in "orbit correction -> measured response"
  widget. It was missing the implementation after an earlier refactoring
- implement notifyEvent in terms of eventFilter. This makes it possible to
  these event notifications, and therefore prevent bugs due to calling dead
  objects.
- turn shell from dockwidget into a normal dialog
- allow opening multiple console windows at a time
- replace qtconsole by the faster and more lightweight pyqtconsole
- this fixes an "AttributeError" when calling "exit()"
- also fixes "Execution aborted" error that prevents further statements from
  being executed in the console after any exception has been raised in a
  previous command
- work on improving documentation and cross-referencing
- use pint 0.9