Changed the composite js content plug-in not to return the list of valid
content paths in all contained content plug-ins, since these can't be
parsed by the content-path-parser this plug-in offers, but to instead
only return content paths this plug-in can create responses for.
Updated the skeleton XML content plug-in so it stops throwing exceptions
when we are trying to create the War.
Ensure the new bladerunner servlet and filter aren't deployed in
production, where they're not needed.
Ensure the temporary guard we have to protect against incorrect use of
the model from non 'brjs-core' code is in both locations where it's
needed.