first draft skip list
values inside skip list
reversed fixed
better _remove{,_all} code, should be correct
break out skip list to FastIter OMD + bench
fix super calls from fast refactor :(
retain ugly super calls, since we don't want OMD's help
Merge remote-tracking branch 'upstream/master' into omd_skiplist
slightly clearer doc string
Merge pull request #2 from markrwilliams/omd_skiplist

Omd skiplist
fix reverse; missing yield from!
Merge pull request #3 from markrwilliams/fix_reverse

fix reverse; missing yield from!