ENH: reorganize the tests into groups by object type
ENH: reorganize the tests into groups by object type

The motivation is that we will have multiple tests for each object type. When a
new test is added, its name would just need to be added to the corresponding group.

QIICR/dcmqi,QIICR/dcmqi,QIICR/dcmqi,QIICR/dcmqi,QIICR/dcmqi