rose task-run: fcm_make: fix options confs

The `opts` setting did not work, because it is already used to indicate
optional configuration. This has been changed to `args`.

Fix `opt.jobs` syntax in document.

Add test battery for this built-in app.
Update CHANGES.md
Merge pull request #996 from matthewrmshin/fix.fcm_make.app

rose task-run: fcm_make: fix options confs