hg outgoing and hg push now support multiple destination. We do the same
for hg bundle. Various other commands needs this kind of behavior and it
would be create to factor this code out for their usage. However this is an
adventure for another time.
They are some minor change to the tests (in addition to the new test for the
- one because I updated a message to plurals,
- another one because the error changed, and I actually find it clearer.