TODO:
* support 1/x axis scale
* SpreadsheetView: implement getBigInt() using QLineEdit with QLongLongValidator inherit from QValidator (see https://stackoverflow.com/questions/19865535/qt-qinputdialog-how-to-validate)
* implement the interruption of running calculations in Maxima, borrow the code from wxMaxima for this
DONE:
* add KUserFeedback on Windows and Mac (Stefan)
* Implement color maps (https://www.kennethmoreland.com/color-maps/)
* support multiple data ranges in plot (T13016)
Links:
* TODO list: T11524
* Windows port: T3118, T11868, T11669
* Mac port: T3196