prefer a global hook for ufunc routines as opposed to per ufunc name, per signature

[tdimitri]

When a ufunc loop is replaced there is no user callback argument, this makes it difficult for the routine being called to know what it is.

I would rather funnel all ufunc loops to a single routine. The current ufunc hook design has fanned out already and I have to write code to funnel it all back into a central routine so I can thread it back out.