Bug 20891: Escape html then JSON

Bug 20891: Escape html then JSON

To my understanding we need to escape first html chars then to JSON.

If this patch works we will need to rethink the 'To' TT plugin.
It was originally designed to have several escape methods, but with
these changes it will not make sense to name it 'To' if used only to
escape JSON

IIRC we should keep the 2 different ways to use it:
 * [% To.json( string ) %]
 * [% string | $To %]
otherwise it will be hard to use it when called in argument of
patron-title.inc (`git grep To.json`)

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>