Jean pretty layout

This can lose some info if the HTML is weird, e.g.:

    >>> ss = u'''<!-- P { margin-bottom: 0.08in; } --><p><b> </b></p><p align="CENTER"><b>TEXT</b><!-- comment --></p>'''
    # First comment is lost
    >>> [e for e in etree.parse(StringIO(ss), parser).iter()]
    [<Element html at b6d9334c>, <Element body at b6d93374>, <Element p at b6d932fc>, <Element b at b6d9339c>, <Element p at b6d932ac>, <Element b at b6d933ec>, <!-- comment -->]
    >>> ss = u'''<b><!-- P { margin-bottom: 0.08in; } --><p><b> </b></p><p align="CENTER"><b>TEXT</b><!-- comment --></p>'''
    # First comment is kept
    >>> [e for e in etree.parse(StringIO(ss), parser).iter()][<Element html at b6d936e4>, <Element body at b6d9370c>, <Element b at b6d932d4>, <!-- P { margin-bottom: 0.08in; } -->, <Element p at b6d93734>, <Element b at b6d9375c>, <Element p at b6d93784>, <Element b at b6d937ac>, <!-- comment -->]

For me the benefits outweigh this concern.