Conflicts:
include/LedCheckBox.h
src/gui/widgets/LedCheckBox.cpp
Adjusted some enums in LadspaMatrixControlDialog.cpp and
LadspaWidgetFactory.cpp.
Note: The following commits made changes to `Knob.cpp` and might need to be
integrated into `FloatModelEditorBase` which was created by extracting
methods and implementations from `Knob`:
* f10277715f: Seems to have only changed enum definitions
* 7000afb2ea: Modifier keys for mouse wheel events
* fcdf4c0568: Show knob value on mouse over
62694d4a4e