* Get rid of "ghost" windows on startup.
Removes hide all docking windows feature for now, to be replaced by a new implementation. Will probably break some tests due to this.
Remove obsolete single summary template code
Always use maximized state of the QMdiSubWindow when a plot or view is deleted.
Move time axis to top
Set correct text for unused axis
Avoid assert when layout is requested for non existing legend
* Create multi summary plot from summary plot(s)
* Rearrange multi summary plot properties
* Enable source stepping toolbar for multi summary plot
* Automatically activate new summary plot when creating from data sources -> data vector tree
* Enable global key controls for switching data in summary and multi summary plots
* Update tooltip texts for summary plot toolbar
