URI breaks query strings containing `=` symbol

If you create a new URI instance using a URL that has a query string property value containing an `=` symbol, the URI class will truncate the value at the point immediately before it appears.

For example:

``` as3
var uri:URI = new URI("http://www.domain.com/foo?bar=la=de-da");
uri.forceEscape();
trace(uri.query); // Outputs: bar=la
```
