agent: Inform client of byte order.

So that it can know what to do with numbers that are in "network byte
order", for example.

Reviewed-by: Stef Walter <stefw@redhat.com>
web: Fix 'interfaceAdded'

by passing the correct data to the DBusInterface constructor.

Reviewed-by: Stef Walter <stefw@redhat.com>
web: Add 'propertiesChanged' method to DBusInterface.

So that we can use other sources of change notifications, such as
explicit GetAll calls or custom PropertiesChanged signals.

Reviewed-by: Stef Walter <stefw@redhat.com>
web: Directly talk to NetworkManager.

Fixes #453

Reviewed-by: Stef Walter <stefw@redhat.com>
daemon: Remove networking API.

Reviewed-by: Stef Walter <stefw@redhat.com>
web: More documentation for DBusClient.

Closes #528

Reviewed-by: Stef Walter <stefw@redhat.com>