Clean up unused variables for lint
Improve `findComponentRoot` Error Message

Instead of simply logging the React ID of the `ancestorNode` when `findComponentRoot` fails, use a `try ... finally` to `console.error` the `ancestorNode`. This allows modern web inspectors to actually log a reference to the node (which may not have a React ID).

This means when people run into the problem, they will not have to execute:

  require('ReactID').getNode(<copy+paste>);

NOTE: Admittedly, this will not log anything in IE8. That's fine, since IE8 has shitty console logging anyway.
Implement `ReactDOMTextarea`

This changes `ReactDOMTextarea` to accept `defaultValue` and `value`. It will warn people about using children (but allow it and treat it as `defaultValue`, which is the current behavior).
Don't keep the HTML escaped ID internally, only in HTML generation

A dynamic value can be provided as a key to a child. Either as part of an object
or key property. This becomes part of the component's ID.

We have to be careful to escape this key before inserting it into the DOM since
it could become a vulnerability. We fixed this by escaping just the keys.

However, the current implementation breaks when you used escaped keys. The
internal value is escaped and the value used by getAttributeNode and
getElementById are both unescaped.

This fixes that by keeping the unescaped value internally but escaping it right
before the HTML is generated (like any other attribute).

This is important since business logic IDs (that should be used as keys)
contains characters that need to be escaped.
use .apply instead of .call in ReactCompositeComponent

This was a bit ridiculous.. let's just use arguments as it's supposed to
be used.