Make local complementation and pivoting work with parametric boolean angles.

[RazinShaikh]

Adding back this issue as it was removed from the previous issue #60

[wlcsm]

Hey @RazinShaikh , could you explain a little more about what this feature should achieve?

[RazinShaikh]

Suppose spiders are labelled with symbolic values such as jpi, kpi, etc. where j, k, etc. in {0,1}. It is possible to perform local complementation and pivoting in a very similar way to the phase-free case. This is an issue to implement this behaviour.