scikit-verify 0.4.3

scikit-verify 0.4.3

• np.piecewise maps to sympy.Piecewise as a dialect entry. numpy's
  last-condition-wins precedence is honored by building the chain
  forward, callable pieces are traced through, extra args pass
  through, and the trailing funclist entry is the otherwise clause.
  A concrete boolean mask still refuses, since there is no symbolic
  condition to recover.
• No other changes.