dillon1000/react

Stop ReactInputSelection breaking in IE8

In the IE code path the method assumed that the input.value property
was non-null. A quick fix is to use either value or innerText; which means
the same code can be shared for textarea and contentEditable components.

The code is slightly buggy because the range.parentElement() !== input check
will fail for contentEditable components when the focus within a deep DOM tree.