ws: Rearrange libssh logging during tests to diagnose travis

Diagnose new test races by rearranging the SSH detailed logging.

Closes #774
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
common: Rename cockpit/ subdirectory to common/

For new contributors it's confusing to have a directory
named 'cockpit'.

And clean up the last vestiges of libcockpit being an installable
library.

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
common: Rename libcockpit.a to libcockpit-common.a

Just to make things clearer

Closes #786
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Fix the debugging manifest.json for removed network js

Otherwise we get 404's when people link the shell module into
their home directory for quick development.

Closes #804
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
ws: Add a firewalld service for cockpit-ws

This allows people to easily open the cockpit port in their
zones with commands like:

 # firewall-cmd --add-service=cockpit --permanent

It also provides the basis for getting this enabled in Fedora Server
by default.

Closes #806
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
Release version 0.13

 * And fix a make distcheck issue
agent: Lock down the executable that cockpit-session runs

cockpit-session runs in a different security context (at least
SELinux) than cockpit-ws. So don't trust cockpit-ws to tell us
which agent to run.

Fixes #607
agent: Don't start a session without authentication

Currently the only form of authentication is password based,
but in the future we'll pass gssapi kerberos input to
cockpit-session for authentication.
agent: Use cockpit-agent instead of test-agent

Remove the unnecessary test-agent program, and just use
cockpit-agent during tests.

Closes #807