Simplify pypfilt.state.repack

We can use numpy.lib.recfunctions.structured_to_unstructured and avoid
raising exceptions under certain conditions, such as the ValueError "To
change to a dtype of a different size, the array must be C-contiguous".

src/pypfilt/state.py

@@ -202,6 +202,5 @@ def repack(svec, astype=float):
         msg = 'Fields {} are not compatible with type {}'
         raise ValueError(msg.format(', '.join(incompat), astype))
 
-    out = numpy.lib.recfunctions.repack_fields(svec).view(astype)
-    new_shape = (*svec.shape, -1)
-    return np.squeeze(out.reshape(new_shape))
+    out = numpy.lib.recfunctions.structured_to_unstructured(svec)
+    return out.view(astype)