Add PV tracks for excited B decays as extra outputs for SL sprucing

Create method to select additional tracks for reconstructing excited B candidates (Bs2*, Sigma b, etc). Would allow analysis

Return is usable as extra_outputs in a line. Configurable with pt, bpv ipchi2, perpendicular momentum, and pid cuts. Default cuts set to select approximately one extra track per candidate as tested with available RTA bandwidth hlt1 filtered samples (limited statistics, though). No PID applied which would cut rate appreciably for Bs2*. I'm unsure of the suitability of default pt cut for Sigma_b states, but lowering it rapidly increases the background rate.

In draft version applied only to D0munu and pipimunu because of previous analysis work. Maybe can extend to a few other modes if rate is acceptable.

Requires fix to SHARE_BPV functor in Rec to properly compare pointers to PVs (won't crash without it but will select nothing).