0.6.0

0.6.0

In the previous release, RestrictedPartHoleDrudge is narrower in scope than
the SpinOneHalfPartHoleDrudge. After some internal revision, now all
problems for SpinOneHalfPartHoleDrudge should be able to be handled with
RestrictedPartHoleDrudge. For expressions with many terms coming from
concrete spin summation, significant speed up can be brought.

To update to the new drudge,

• When your theory is already based on unitary group generators, just remove
  your definition and use the definition from the drudge.

• When your theory is not written in terms of unitary group generators, it is
  strongly advised that your theory is rewritten in terms of them. If it
  really cannot, use symbolic summation over spin values as much as possible.

• Even when the spin values are never summed abstractly, simply change the
  drudge to this new one might still be beneficial.