Fixed error in IE that prevents logs from showing

IE doesn't clone completely empty text nodes on cloneNode(true), see http://jsfiddle.net/SFqk9 for an example.
This results in a null reference exception when setting span.lastChild.nodeValue in the renderSpan function. By putting a space char in the text node this doesn't happen as the node gets cloned correctly.
Merge pull request #8 from akoeplinger/master

Fixed error in IE that prevents logs from showing