When attribute values contain both an apostrophe and a double quote,
we should substitute the character being used to wrap the value with
its key code instead of named/keyword entities (for IE support).
Fixes#418.
Signed-off-by: Norman Clarke <norman@njclarke.com>
If the mime_type of the ActionView::Template template
being rendered is 'text/xml' then add the a :mime_type
key to the options hash so Haml::Engine will force a
format of xhtml.
Closes#427
Signed-off-by: Norman Clarke <norman@njclarke.com>