vtkCompositeCutter adds the following functionality:
- it loops over all data sets in a composite data set input
- it uses AMR meta information, if availble, to compute intersecting
data sets and only requests those.

There is a also a change in the AMR reader so that meta data can be
generated for partial AMR.

Change-Id: Ifc8f498c2cf56945f899ffa5785e0bc91acdec97