* 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
Improve robustness related to update of Summary Plot Manager
Add RimSummaryMultiPlot
Move shared code into RiaSummaryStringTools
Added "Create Summary Multi Plot" to menu of MultiPlot in project tree
