for each functinoal module API one test framework for each module

e.g. loading forward projector e.g. different voxel size, anatomies .
Fin for the test

1. input_data
2. think: is the output data
3. output_data (has to be similiar to the output of the old version, the expected results can direcly be stored in the unit test) e.g. def decompose() unit test1: input data is like X //maybe own data
   unit test2: input data is like Y // data from siemens unit test3: input data is like Z // e.g. use the calibratio phantom