Implement, test and benchmark findMin and findMax.

--HG--
extra : rebase_source : 7c648ec2765b8df88425c078e1ecb44659d792b9
extra : histedit_source : e016c92022737f29bab58861e0cbabec489eee7c
Implement deleteMin, deleteMax, deleteFindMin, deleteFindMax

--HG--
extra : rebase_source : f62ee347ea5b6de15c4f288d67827d96677c5b1d
extra : histedit_source : 5a694e0e358baea7f2e2aaf02313fe4e2335a06f
Pull leftmost/rightmost functions to top level.

--HG--
extra : rebase_source : 07174380cc9c7a0a09bf18cd707a44cc60be0313
extra : amend_source : 35afdf933724db2f02ad58919e302aeb4c6d6650
extra : histedit_source : e28d53fdea7cb33c695b84f894723541c214dd6b
A little reformatting
Better tests for deleteFindMin / deleteFindMax
Merge
Merge