update backburner

included updated documentation for the run loop as well
DRY up container tests.
[FEATURE ember-metal-computed-empty-array]

Make `Em.computed.empty` respect arrays automatically, without users having to
know to use `array.[]`.
[BUGFIX beta] Make Ember.RenderBuffer#addClass work as expected.
Lazily setup observers for attributeBindings without defined values
Define HTML5 fields on input fields.

Previously, binding to this many attributes unnecessarily added a
significant performance penalty. Now these bindings are setup lazily for
values that were not previously defined on the instance.
[beta] Sync route-recognizer

Doesn't really fix "bugs" but provides more sensible sorting logic
preferring less dynamic routes to more dynamic routes, particularly
when star segments are involved.

See https://github.com/tildeio/route-recognizer/pull/22
Remove controlID inclusion from mustache
Add automated testing for prod/min builds.
Merge pull request #4269 from marcioj/old_control_helper_stuff

Remove controlID inclusion from mustache
Merge pull request #4270 from rjackson/test-minified-builds

Add automated testing for prod/min builds.
Merge pull request #4257 from rjackson/lazily-bound-attributeBindings

Lazily bound attribute bindings
Merge pull request #4237 from rjackson/dry-container-tests

DRY up container tests.
Merge pull request #4219 from hjdivad/make-empty-less-confusing

[FEATURE ember-metal-computed-empty-array]
Merge pull request #4120 from kingpin2k/update_backburner

update backburner and Ember Metal documentation
Merge pull request #4267 from machty/syncrr

[beta] Sync route-recognizer
[beta] sync router.js

Brings in a change which prefers internal rejecting promises to
`throw`, which was causing Pause on All Exceptions to pause
on internal stuff in response to simple things like redirecting.
Note that in the case of actual errors, Pause on All Exceptions
will continue to pause on the original error that caused any
unintentional redirects, so, hooray.
Merge pull request #4272 from machty/im-syncing-in-the-brain-one-is-a-genius-the-other-insane

[beta] sync router.js
[BUGFIX beta] Still update HTML5 history if the previous state was null

Fixes #3195, Closes #3580
Pre-fill the ember.js tag in the SO link

Also change StackOverflow to Stack[space]Overflow, see the any page title or footer for proof.