Add webdav channel

See spice-common for protocol details.  phodav, a webdav server library,
is imported thanks to a submodule, until this project has a stable API
and releases.

The webdav channel is reponsible for handling port events and
multiplexing the request streams. Extra care has been made to avoid
blocking and to enable some fairness between concurrent streams, however
this has been particularly tricky and is likely to have some issues
left.

The webdav server is run in a seperate thread, using libsoup. The client
communication is done via a local tcp socket, but protected to only
accept local connection and with a pretty strong password.

The home directory is exported for the remote to browse, which seems to
be a sensible default atm.

1 files changed, 0 insertions, 0 deletions

diff --git a/spice-common b/spice-common
-Subproject 96ca358669cd32d17ce51f30de3cdbf0a1c0518
+Subproject 01955e70079876de62bb8c86ee6793c1405fb47