This is more UI standard than the combo in bottom right corner.

As a consequence, hide the always empty status bar (for all views) and with this win more space for relevant content.

* reduce indirections
* reduce redundancy
* implementations in analogy to sample view
* rm job view docks class (integrated into jobview)

* reduce indirections
* reduce redundancy
* rm sample view actions class (had barely any functionality)
* rm sample view docks class (integrated into sampleview)

replace Manhattan::ProgressBar by QProgressBar

This fixes the issue 2503 (GUI: Material editor is a semi-modal toplevel window instead of modal dialog)

http://apps.jcns.fz-juelich.de/redmine/issues/2503

replace Manhattan::MiniSplitter by QSplitter

GUIHelpers::Error::what() returned a char* to a temporary QByteArray which is invalid after leaving what()