_addReference, to mirror _removeReference
Merge pull request #2838 from tgriesser/addReference

_addReference, to mirror _removeReference
Close #2847 assume obj as an id first in Collection#get
Fix #2850 - Use `hashChange: false` where appropriate.
Style tweak, remove jQuery dependency.
Merge pull request #2852 from braddunbar/style

Style tweak, remove jQuery dependency.
Merge pull request #2851 from braddunbar/old-ie-tests

Fix #2850 - Use `hashChange: false` where appropriate.
Clarify bindAll and events hash `this` binding in FAQ section
more specific bindAll warning
Merge pull request #2854 from akre54/bindall-docs

Clarify bindAll and events hash `this` binding in FAQ section
Tweaking 'this' FAQ
Fixes #2833 — document bound comparator woes in the appropriate spot.
Fix #2846 nested "change" events trigger with correct options
Merge pull request #2856 from jashkenas/gh-2846

Fix #2846 nested "change" events trigger with correct options
UMD wrapper for AMD, node and browser globals.
Adding AMD support to Backbone.
Improve events performance in some cases by 20x.

Things like [Chaplin](http://chaplinjs.org) are using advanced memory management heavily. This includes unbinding of all events too.

Events are getting unbound all the time. When other objects may still try to trigger events, this will increase performance by 20x.

Initially taken from [my Backbone optional-dependencies fork](http://exosjs.com).

Proof of 20x speed: http://jsperf.com/exoskeleton-events-vs-backbone-events
Adding Bower and Component files.
Merge pull request #2858 from paulmillr/patch-1

Improve events performance in some cases by 20x.
Fix AMD tests. jQuery is modern enough that we dont need a shim. Remove JSLitmus, and add in stubbed xhr environment file