Point people to the the-tcpdump-group repositories, not the mcr repositories.

We've created a the-tcpdump-group organization on GitHub, and created
repositories for libpcap and tcpdump, owned by them.  Those are now the
"official" GitHub locations for repositories from which to clone or
against which to file issues/pull requests.
Merge branch 'master' of git+ssh://bpf.tcpdump.org/tcpdump/master/git/libpcap
Add DLT_DBUS to the table of link-layer type names
Add support for Linux Kernel Messages

This feature use /dev/kmsg for capturing Linux kernel messages.