This commit is generated using regex based find and replace:
```
s/[\w:]+_cast\s*<([^>]+)\*>\s*\(\s*getObject\(\s*\)\)/getObject<$1>/
s/[\w:]+_cast\s*<([^>]+)\*>\s*\(\s*([^)]*)\s*->\s*getObject\(\s*\)\)/$2->getObject<$1>()/
```
To regenerate if needed.
- fix bug that changing constraint type in dialog lost flux value
- accept and not immediately save any changed value
- make the temperatures a PropertyTemperature to get rid of hacks
- also fix some too long code lines
* Now the behavior is consistent with behavior of PD fillets, for example.
See https://forum.freecadweb.org/viewtopic.php?f=18&t=67135#p580192. In the
future it may be possible to reuse some code from there.
* When the last selected item is removed we need to reset the existing
highlighting separately.
* Use `Gui::ButtonGroup` in `TaskFemConstraintOnBoundary`
Use the previously added superclass `TaskConstraintOnBoundary` for more
constraints where it's usable.
Currently done:
TaskFemConstraintDisplacement
TaskFemConstraintForce
TaskFemConstraintSpring
TaskFemConstraintFluidBoundary
TaskFemConstraintHeatflux
TaskFemConstraintFixed
TaskFemConstraintTemperature
TaskFemConstraintPressure
Too different:
TaskFemConstraintTransform (single selection)
TaskFemConstraintContact (single selection, two fields)
TaskFemConstraintPlaneRotation (single selection)
(Other constraint tasks, which do not use `addToSelection`)
