#57 Node interface for start and end tag start and end positions

Currently, the Node interface offers the Node.getStartPosition() and Node.getEndPosition() methods. This is not that useful. What I often need is the start and end position of the closing tags, too. AFAIK they must be calculated manually. You should change the interface to reflect:

getStartTagStartPos()
getStartTagEndPos()

and

getEndTagStartPos()
getEndTagEndPos()

This would be much more useful.