[Bugfix beta] stop using Binding#directionMap once binding per instance
[Bugfix Beta] avoid unneeded Function#apply
[Bugfix beta] fix map: turns out 0 is also falsey
Merge pull request #9282 from stefanpenner/fix-map

[Bugfix beta] fix map: turns out 0 is also falsey
Merge pull request #5625 from stefanpenner/remove-binding-direction-map

Remove binding direction map
update back burner

Diff: https://github.com/ebryn/backburner.js/compare/919861fa9f3a5504c37f05607b1b02421af04167...baef3625dd4374e3803288652cd0aab68775cc62

* [Cleanup]unify deferredActionQueue.flush and queue.flush
* [Perf] reduce cost of flushing and dramatically reduce cost of flushing empty queues.
Merge pull request #9288 from stefanpenner/update-bb

update back burner
MISC Cleanup
use faster x[y] over y in x, as all hits will be explicitly truth
remove unused toDOM method
Merge pull request #9292 from stefanpenner/cleanup

Cleanup
Removed redundant conditional

The current block it was in already guarantees `callback` is truthy so it was frivolous.
Merge pull request #9299 from jayphelps/patch-4

Removed redundant conditional
Streamify template bindings