IE8 support

I needed this library to work with IE8. (because it's a dependency of yields/select) The changes here are not as drastic as I expected, so I hope it will be considered for inclusion.

 * using `component/each` instead of `Array#forEach`
 * using `juliangruber/isarray` instead of `Array.isArray`
 * using `innerText || textContent` fallback for text
 * using `matthewp/text` for tests (could not use in lib because document-fragments don't work like normal nodes in IE8)
 * adjusted some unit tests to account for "differences" with IE8 (capitalizing tag names, etc)

All unit tests continue to pass in other browsers, and IE8 now passes too. (with one exception being the component/enumerable#25)