Added length property to Ember.Map
Adds the ability to specify the view class used by the outlet Handlebars helper

Previous to this change, the view class used was always an "OutletView" (Metamorph extension of ContainerView).  This change allows the class to be set while still defaulting to the OutletView
Adding regression test
Make router's render idempotent

This change prevents us from tearing down and recreating a view when
the new view is functionally identical to the old view.

This has important benefits:

 - when you're changing context within a route, the view itself
   remains stable, and the controller has full control over how and
   when to update the data it's presenting to the view
   layer. (Previously, you got a forced re-render immediately whether
   you were ready for it or not.)

 - when you're changing between routes, you can decide to keep the
   prior view in place, and replace it later when you're ready. (Think
   animated transitions between routes.)

This supercedes the proposed changes in PR #2563 (which has already
been reverted).
Clean up pendingDisconnections propertly
deprecating some of the defaultContainer's methods
changing deprecate to deprecateFunc
reverting previous change back
Merge pull request #2594 from twokul/master

restore defaultContainer for now, but deprecate it
default input helper to type="text" if no type given
fix defaultContainer deprecation warnings.
Merge pull request #2598 from fivetanley/default-input-type-is-text

default input helper to type="text" if no type given
Adds disabledWhen option to {{linkTo}} helper
Merge pull request #2600 from stefanpenner/fixup_deprecation_warnings

fix defaultContainer deprecation warnings.
Merge pull request #2436 from trek/disabled-linkto

Adds disabledWhen option to {{linkTo}} helper
More accurate, helpful error message for handlebars version errors.
Merge pull request #2602 from mixonic/explicit-version-matching

More accurate, helpful error message for handlebars version errors.
Don't add disabled class if disabledWhen not provided
Merge pull request #2607 from bradleypriest/disabledWhen

Don't add disabled class if disabledWhen not provided
Improve {{render}} docs.

Updated to clarify the different behavior when passing a single argument
versus two arguments.