Modify the way filters are added to the server. Instead of using a FIFO,

we use a modified LIFO.  It is modified, because if we add a filter while
in the middle of another filter, the added filter gets put in after the
current filter.  This requires that the server is smart about which filters
are added when.  This should be handled by the HTTP protocol, but we will
want to keep and eye on things for a little while.

This change is necessary, because currently when we add a filter it goes
after the last filter of the same type.  This is broken whenever we want
to add a filter that has a dependancy.  Think about the core and chunking
filters.  They are of the same type, and core is always added first.  When
we go to insert chunking, it gets added, but it is never called.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@86161 13f79535-47bb-0310-9956-ffa450edef68