Include sshuttle version in verbose output.

Some bug reports include verbose sshuttle output but lack the version
that is being used. Including the sshuttle version in the output may
make it easier to handle future bug reports.

sshuttle/client.py

@@ -17,6 +17,7 @@ from sshuttle.ssnet import SockWrapper, Handler, Proxy, Mux, MuxWrapper
 from sshuttle.helpers import log, debug1, debug2, debug3, Fatal, islocal, \
     resolvconf_nameservers
 from sshuttle.methods import get_method, Features
+from sshuttle import __version__
 try:
     from pwd import getpwnam
 except ImportError:
@@ -581,7 +582,7 @@ def main(listenip_v6, listenip_v4,
         except Fatal as e:
             log("%s\n" % e)
             return 5
-    debug1('Starting sshuttle proxy.\n')
+    debug1('Starting sshuttle proxy (version %s).\n' % __version__)
 
     fw = FirewallClient(method_name, sudo_pythonpath)