Fix incr file install symlink mode to normal mode

Fix rose.config_processors.file: in incremental mode, when
`mode=symlink` is removed from a target, the target should be recreated,
instead of being left to point to a symlink.
rose suite-scan: fix call with argument

`rose suite-scan HOST` was broken.
Add test-battery.
Merge pull request #846 from matthewrmshin/fix-rose-app-run-file-symlink-remove

Fix incr file install symlink mode to normal mode
Remove requirement for '@' in task hosts.
Fix typo.
Merge branch 'master' into fix-rose-suite-scan
Merge pull request #848 from arjclark/fix-ssh-user-bug

cylc.py: Remove requirement for '@' in task hosts.
Merge pull request #847 from matthewrmshin/fix-rose-suite-scan

rose suite-scan: fix call with argument
Update CHANGES.md