add changeIndex to track grid changes
In order to track changes of the mesh due to grid adaption, a changeIndex is introduces that is increased after each adaption step. This allows to optimize some code when the grid is not changed.
In order to track changes of the mesh due to grid adaption, a changeIndex is introduces that is increased after each adaption step. This allows to optimize some code when the grid is not changed.
This will create a new commit in order to revert the existing changes.