5.2.7.2 noescape attribute

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5.2.7.2 `noescape` attribute

The `noescape` attribute can be used to suppress escaping of the `src` (5.2.7.3) attribute.

    >>> import albatross
    >>> ctx = albatross.SimpleContext('.')
    >>> ctx.locals.url = 'http://www.com/img?a=1&b=2'
    >>> albatross.Template(ctx, '<magic>', '''
    ... <al-img expr="url" noescape whitespace>
    ... ''').to_html(ctx)
    >>> ctx.flush_content()
    <img src="http://www.com/img?a=1&b=2" />