Exception in case of non-quadratic pixels of the input images.

If the pixels of the input images are not quadratic, AROSICS raises a RuntimError during shift calculation:

RuntimeError                              Traceback (most recent call last)
<ipython-input-8-09998254e4f0> in <module>
      5 
      6 CR = COREG(ref, tgt, wp=(581752, 5619576), ws=(256,256), max_shift=15)
----> 7 CR.calculate_spatial_shifts()

~/arosics/arosics/CoReg.py in calculate_spatial_shifts(self)
   1225 
   1226         # set self.matchWin and self.otherWin (GeoArray instances)
-> 1227         self._get_image_windows_to_match()  # 45-90ms
   1228 
   1229         im0 = self.matchWin[:] if self.matchWin.imID == 'ref' else self.otherWin[:]

~/arosics/arosics/CoReg.py in _get_image_windows_to_match(self)
    817                              'get_image_windows_to_match. Reference image shape is %s whereas shift '
    818                              'image shape is %s.' % (str(self.matchBox.wp), self.matchWin.shape, self.otherWin.shape)),
--> 819                 warn=True)
    820 
    821         # check of odd dimensions of output images

~/arosics/arosics/CoReg.py in _handle_error(self, error, warn, warnMsg)
    331 
    332         if not self.ignErr:
--> 333             raise error
    334 
    335     def _set_outpathes(self, im_ref, im_tgt):

RuntimeError: Caught a possible ProgrammingError at window position (581752, 5619576): Bad output of get_image_windows_to_match. Reference image shape is (256, 256) whereas shift image shape is (418, 256).