* Use identical logic to select when stdout/stderr are merged, so
'stdout', 'stdout_lines', 'stderr', 'stderr_lines' contain the same
output before/after the extension.
* When stdout/stderr are merged, synthesize carriage returns just like
the TTY layer.
* Mimic the SSH connection multiplexing message on stderr. Not really
for user code, but so compare_output_test.sh needs fewer fixups.
- Add new Travis mode, "ansible_tests.sh" that runs
integrations/all.yml. Slowly build this up over time to cover more of
the existing junk.
- Add basic assertions on the output of the existing runner__* files.
- Wire up 2.4.3/2.5.0 jobs in Travis.