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.
Fix broken link
Added 1.0.0-rc.1 JSBin and JSFiddle
Remove unused variables
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
Merge pull request #2089 from tricknotes/fix-broken-link

Fix broken link
Merge pull request #2091 from tricknotes/remove-unused

Remove unused variables
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
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)