Quick fix to remove old legacy library that was supposed to be

removed in previous release. No big deal, it just confused the
YARD documentation.

This is a complete rewrite to simplify the design and use more

of Ruby's internal methods.  Overall performance should be markedly
improved. A few method names have changed to be more consistent with
Ruby's other data structure. Note that the internal heap is now in reverse
order from the previous version. If using #to_a be aware that the priority
order will be reversed. This release also switches the library to
distribution under the BSD-2-Clause license.