Allow ELResolvers filtering

related to topic
http://www.mail-archive.com/dev@myfaces.apache.org/msg49177.html

Problem:
how to disable ELResolver smartly? Adding a context-param for each is an
overkill.

But we have https://cwiki.apache.org/MYFACES/elresolver-ordering.html in
codebase already. I propose to add new feature "ELResolver filtering"
and new context-param:

<context-param>
<param-name>org.apache.myfaces.EL_RESOLVER_PREDICATE</param-name>
<param-value>org.foo.bazz.ELResolverPredicate</param-value>
</context-param>

Filter is simple instance of org.apache.commons.collections.Predicate.

For application where no ManagedBean(Resolver) is used or no Flash, user
can simply return false from Predicate.evaluate and ELResolver won't be
installed.

See mail thread here: http://www.mail-archive.com/dev@myfaces.apache.org/msg52082.html