ENH: additional BitOps::toc, BitOps::sortedToc

- for obtaining set entries from a boolList

- BitOps::select to mirror bitSet constructor but returning a boolList

- BitOps::set/unset for boolList

ENH: construct bitSet from a labelRange

- useful, for example, when marking up patch slices

ENH: ListOps methods

- ListOps::count_if to mirror std::count_if but with list indexing.
- ListOps::find_if to mirror std::find_if but with list indexing.

ENH: UPtrList::test() method.

- includes bounds checks, which means it can be used in more places
  (eg, even if the storage is empty).