* Avoid creation of curve legend widgets during construction of a multi plot
* Make sure default z-value is correct to avoid expensive Qwt updates
* Avoid duplicate plot updates
* Do not create internal Qwt legend by default
* RFT import: Avoid expensive method throwing exception if no data is found
- add copy paste of plots into multi summary plot
- improve data source stepping for multi plot
- improve auto generated plot name, graph name and curve name
Fixes by clang-format
Improve readability
