Non-HTML-encoded HTML-template data causes problems in HTML
even when it appears inside JS string (resulting in the <script> tag being
closed by a </script> appearing inside a JS string).
Besides, the KIWIX_RESPONSE_DATA and KIWIX_RESPONSE_TEMPLATE variables
are set on the window object so that they can be accessed from the top
context.
This commit eliminates the need for the `escapeQuote` parameter in
`escapeForJSON()` (that was introduced earlier in this PR) since now it
is set to false in all call contexts. However from the consistency point
of view, the default and intuitive behaviour of `escapeForJSON()` should
be to escape the quote symbols, which justifies the existence of that
parameter.
This is a shortcut change since it doesn't make sense to send the error
page template with every error response (the viewer can fetch it from
the server once but that's slightly more work).
404.html no longer contains anything specific to the 404 error and will
henceforth serve (with some enhancements) as a general purpose error
page template.
Veloman Yunkan