[FEATURE em-o] Added `Em.O` (shorthand for `Ember.Object.create`
[BUGFIX beta] Fixes issue when content is undefined for Ember.Select with optgroup

If the content given is undefined at the time of initialization, and
later changed,
`Ember.Select` correctly renders an empty select and then updates the
content  [Example](http://jsbin.com/epodAwU/14/edit),
But `Ember.Select` with `optgroup` breaks.
[Example](http://jsbin.com/IJaToVO/1/edit).

This breakage may happen, when the content for the select is fetched
via an ajax call to the server.

This PR fixes it.
Update route recognizer
Fix documentation for Ember.Select multiple and disabled attributes
fix a typo in container docs
Merge pull request #3420 from goshakkk/container-docs-typo

Fix a typo in container docs
Adding comments for 'extend()' method

Additional comments

Added comments for Mixins

Added example using Ember.Mixin

Added some description of create() vs extend()
Fixed documentation of computed.mapBy. Typos and removed unreferenced second computed property
Merge pull request #3389 from graup/docu-computed

Fixed documentation of computed.mapBy.
add a 'readonly' binding to TextSupport
Merge pull request #3423 from goshakkk/text-support-readonly

Add a 'readonly' binding to TextSupport
Test with all feature flags enabled.
Fix documentation and inconsistent usage for Ember.deprecateFunc()
Fix the second half of the bug in suspendListeners

If the same listener was the action for two events, this would result in
only the second event becoming un-suspended, because the first event's
actions would be overridden.
Merge pull request #3425 from rjackson/test_with_feature_flags

Test with all feature flags enabled.
[FEATURE ember-testing-wait-hooks]

In integration testing, sometimes it's necessary to make `wait` respect
other kinds of pending actions that are not in its default
implementation. For example, if your application is waiting for a CSS3
transition or an IndexDB action, the default `wait` implementaiton will
ignore those things and move on with the test prematurely.

This change lets you register additional functions that `wait` will call
to see whether it's really time to move on.
Fix typo in link-to docs.
Merge pull request #3338 from davidmcch/master

Adding comment to extend() function
[BUGFIX beta] Added tests failing for issue #3331
[BUGFIX beta] Fire observers for array computed changes.

When dealing with chains of arrays, it is not necessary (or correct) to fire
non-array observers when array contents change, but the array itself does not.

However, for other `ReduceComputedProperty`s, such as `Ember.computed.max`, it
is necessary to fire observers in response to upstream array changes.

Thanks @ssured for pointing this out, and for providing tests!

Fix #3331 #3354.