(#35) Fix errors in IE 8 and older

This pull request addresses issue #35.

Without this patch, IE 8 raises the error "Object doesn't support this property or method" and fails to parse.  One error was caused by `match()` being called on a `CSSStyleDeclaration` object instead of a `String`.  Another error was caused by `window.Node` being undefined in IE 8 and older.  This patch checks for `match()` to be a function before calling it.  This patch also defines `window.Node` if it needs to be defined.