BF,RF: Fix a few bugs, adjust `evalHeader` routine

Adjusted the evalHeader routine - now it compares dim and pixdim for all valid dimensions by default. The alldims parameter has been replaced with a ndims parameter, allowing the number of dimensions to be set (e.g. when you only want to compare the first three dimensions).

enabled an automatic merge when all merge checks for 1f1b86ea pass

merged

mentioned in commit cb422081