Strip tags

Added ignore parameter to stripTags function

    _('<html><body><span class="underline">hello</span> <em>world</em></body><!--comment--></html>').stripTags('<span><em>')

will produce:

    <span class="underline">hello</span> <em>world</em>


passing keyword 'inline' will ignore all inline elements
   
     _('<html><body><span class="underline">hello</span> <em>world</em></body></html>').stripTags('inline')