Added in bdaa530. I have also made this style of printing tensor product optional and not used by default. But it can be activated by setting a flag using the function `combined_tensor_printing` (not imported by default) in the tensorproduct module.

The reason for this is that the compromise that you suggested undermines the usefulness of this (rather standard) notation, because I think is very useful when mixing quantum systems of different type, such as a resonator and a spin, or something like that. If the notation only works for bosons and fermions I think it is not much point in having it, and with it now being inactivated everything is by default displayed with explicit tensor product symbols as you wanted it, but the simplified notation is still available if one explicitly requests it (with `combined_tensor_printing(True)`).