MSHTML VBufBackend: filter all whitespace from text nodes so that there is no whitesp...

MSHTML VBufBackend: filter all whitespace from text nodes so that there is no whitespace at the beginning or end of a node, and all whitespace between non-whitespace is collapsed down to one space character. This stops many annoying blank lines appearing in virtualBuffers of Internet Explorer 9 documents. The reason for the extra whitespace in Internet Explorer 9 is: IHTMLDOMTextNode::get_data in Internet Explorer 9 gives back text including *all* whitespace existing in the source markup (including simple linebreaks to make the html more readable), where as previous Internet Explorer versions did not contain this whitespace.