Remove reference to therubyracer from README.md 

therubyracer doesn't currently work to build ember.js, and this patch removes an instruction to use it.
add Ember.computed.defaultTo
Controllers are unwrapped

When a controller is passed to {{action}}, its
model is passed to the target
Move resolution logic to shared file
Unwrap controllers passed to {{linkTo}}
lastObject should not raise exceptions on empty arrayControllers

It fix an error introduced in c97a01947ea05654121cc8211908375637e4a7ac
Merge pull request #2142 from tchak/array-controller-fix

failing test with default arrayController content
Fix two linkTo unit tests that fail in IE9.  Tests used an <a> tag inside of a <button> tag, which IE9 does not like but works in other browsers.  Example: http://jsbin.com/ozemig/1/edit
Normalize controller lookup, fix #2025
Merge pull request #2145 from craigteegarden/ie9-linkTo-test-fix

Fix two linkTo unit tests that fail in IE9.  Tests used an <a> tag insid...
Merge pull request #2131 from darthdeus/normalize-controller-lookup

Normalize controller lookup, fix #2025
Reuse path variable
Refactor normalization
Merge pull request #2152 from darthdeus/fix-normalization

Refactor normalization
Merge pull request #2151 from caligo-mentis/reuse_variable

Reuse path variable in Ember.HashLocation
Use ENV var to disable version logging of used libraries
Merge pull request #2090 from regularfry/master

Patch to avoid bumping into issue #2069
object proxy defines properties that are passed to create that do not exist in the prototype
expose RSVP on the ember namespace
Merge pull request #2162 from stefanpenner/master

Expose RSVP on the Ember namespace