Move the lru timestamp to objcore.  Not sure how we managed to forget
that in obj.
Move the ws_o structure from struct obj to busyobj, and shave 48 bytes
off stored objects.

We used to need this in struct obj, so we could munge obj.http, but
we don't allow that any more.
Rename cache_response.c to cache_http1_deliver.c and make it responsible
for all deliveries, streaming or non-streaming
New VTLA:  V1D - HTTP1 delivery
Also rename the function calls.
Move code around
minor polish
Add yet a VTLA: "VDP" Delivery processors

These are stackable, and does stuff on the way out.

The bottom one points to HTTP/1 ie. WRW for now.

On top of that we can push Range: processing.

Modularizing this, makes it trivial to enable Range: support for
delivery-side gunzip.

(Committed above the Elbe)
Turn delivery-side gunzip into a VDP
Polish
Make the VDP ptr argument const
Polish
Fix buglet
Fix a fine point in this test-case:  We can get a Content-Length on
a 304 response, but we still don't get the body.
Fix other 304 return cases to not expect a body
IMS decision is protocol-independent
Single test for Range-qualifying request
Move the stream-stopper all the way to where streaming will happen
Atomically grab the busyobj, if there is one.
Stream.

(Don't tell me nothing good ever comes from DB's delayed trains...)