"Status Bar" menu entry not updated on switching child window

[codeling]

The "Status Bar" menu entry in the "Window" menu should always reflect whether the currently active window does show its status bar; currently, its checked state only changes whenever the user clicks on it; it should however also adapt to the viewing state of the status bar if another window is activated.

Steps to reproduce:

• Open at least two files in open_iA
• Click the "Status bar" menu option in the "Views" menu
• The "Status bar" entry gets unchecked, and the status bar of the current window is hidden.
• Then switching to another opened child windows(mdichild.h); this still has a status bar; but the checked state of the "Status Bar" menu entry does not get properly updated.

Hint: open_iA uses an mdi area with multiple MDI windows; MainWindow::updateMenus is called whenever the user switches between different mdi windows (via the QMdiArea::subWindowActivated signal).

[codeling]

Status bars are now completely removed in main/develop in favor of a job list widget (where all running operations are listed with their progress).