Fix a typo
Improve performance on large DOMs

When the container is the document, there's no need to be fancy when
loading Elemental and search for attributes of [data-behavior]. We know
we can simple search the entire document.

This is especially helpful on IE8, where the .filter() for attribute
selectors is super slow.
Merge pull request #10 from iwz/large_dom_performance_fix

Large dom performance fix