t: rose-suite-run: log options tests.

The new test file takes quite long to run, so I have added `-s` to the
`prove` command as a default. This should encourage late bottle necks to
start early.
rose test-battery: even more processes.
t:rose-suite-run: test `-O KEY` option.
Doc: fix typo.
rose.popen: print `return-code` instead of rc

Supersede metomi/rose#778, but use hyphen instead of space between
`return` and `code`. This should make it easier to parse.

Modify `rose test-battery` for the change.
Merge branch 'master' into t.rose-suite-run.05-log
Merge pull request #782 from matthewrmshin/popen-return-code

rose.popen: print `return-code` instead of rc
Merge branch 'master' of github.com:metomi/rose into gh-pages
Merge branch 'gh-pages' of github.com:metomi/rose into gh-pages
Merge pull request #777 from matthewrmshin/t.rose-suite-run.05-log

t:rose-suite-run: more tests
Merge branch 'master' of github.com:metomi/rose into gh-pages