Guard against render(undefined)

render(undefined) was doing absolutely horrible things. I found this
problem because I passed an undefined variable as the first argument.
This ended up changing containers on controllers and doing other
absolutely horrible things.
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.
Fix code comment

- Add missing arguments
- Fix order of type and argument name
- Fix argument name
Add missing arguments in code comment
Fix typo

- a Ember -> an Ember
Fix missing reuturn in CollectionView docs

`createChildView` has to return the call to `this._super`, otherwise
everything breaks.
lookup(fullName, { singleton: false })
String.prototype.camelize lowercases the first letter
Change `Route.map` to `Router.map` in docs
Render with a model should not share controllers
Corrects ember-application package description.
Fixes small typo in controllersFor deprecation
Merge pull request #2097 from sheldonnbbaker/patch-1

Change `Route.map` to `Router.map` in docs
Merge pull request #2096 from jamesarosen/fix_camelize

String.prototype.camelize lowercases the first letter
Merge pull request #2093 from darthdeus/collection-view-docs

Fix missing reuturn in CollectionView docs
Merge pull request #2092 from tricknotes/fix-document

Fix document
Cleanup {{each}} documentation
Merge pull request #2015 from twinturbo/render-fix

Guard against render(undefined)
Don't use a sub-container for itemController

While implementing this, I noticed that moving
an item inside an ArrayController that uses
itemController won't work (since it will get
destroyed synchronously). I tried to defer
destruction, but ran into complexity involving
null or duplicated elements.

This commit does not regress existing
functionality, but I figured I would call it out.
Merge pull request #2098 from darthdeus/cleanup-each-documentation

Cleanup {{each}} documentation