This is by no means done, and needs more tests, docs and bugfixes,
but push it early so we have a common base to work on.
Based on work by Martin Sehnoutka.
Signed-off-by: Tom Gundersen <teg@jklm.no>
Keep main.go files under cmd/ and internal libraries under internal/.
This will allow us to add more exutables under cmd/ (whereas only one
was possible when main.go was kept in the root).
Signed-off-by: Tom Gundersen <teg@jklm.no>