This patch enables the filtering of a threaded view which uses
server-built threads. Filtering is done server-side, in order to
preserve the use of server-built threads.
In adding this feature, the filtering of notmuch folders was brought up
to feature parity with the other workers. The filters function the same
(ie: they can be stacked). The notmuch filters, however, still use
notmuch syntax for the filtering.
Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>