Merge pull request Workiva#135 from alexandercampbell-wf/update_readm…

…e_set

README: update to point to alternative Set impls

Merge pull request Workiva#137 from funny-falcon/selectable_future

futures/Selectable - future with selectable completion channel

Merge pull request Workiva#139 from mikeatlas/queue-peek

added queue.Peek() functionality

Merge pull request Workiva#133 from Theodus/master

Bitmap

Merge pull request Workiva#132 from Theodus/master

remove atomic counter from iteration test

Merge pull request Workiva#131 from Theodus/master

Dtrie

Merge pull request Workiva#128 from tylertreat-wf/ctrie_remove_hash_pool

Remove hasher pool from ctrie

Merge pull request Workiva#127 from Workiva/fix_avl

Fix deletion bug due to incorrect node copy.

Merge pull request Workiva#123 from tylertreat/fixes

Fix Ctrie snapshotting

Merge pull request Workiva#124 from brentp/isempty

fix bitarray/IsEmpty()