rose.stem: fix `rose` global name.

N.B. `rose` was implicitly imported by `import rose.run` before #741.
Merge pull request #745 from matthewrmshin/fix.rose-stem.import

rose.stem: fix `rose` global name.
rose.suite_run: fix bad variable name.

Bug introduced in #741 by a rename.
Merge pull request #746 from matthewrmshin/fix.rose.suite_run

rose.suite_run: fix bad variable name.
Update CHANGES.md
Update README.md
rose.fs_util: improve symlink logic.

Add filename to OSError if target exists.
Don't use os.path.exists for testing existence of symlink. It does not
work on broken link.
Merge pull request #747 from matthewrmshin/symlink.e.filename

rose.fs_util: improve symlink logic.
Added roses directory vs. cylc directory comparison image.
HTML tidy up.
Merge pull request #748 from arjclark/cylc-run-vs-roses

#602: Documentation - Add roses vs. cylc-run comparison image.
rose test-battery: add `skip` function.

Add basic tests for `rose host-select`.
rose test-battery: add `rose suite-hook` tests.
t:rose-suite-hook: remove unnecessary files.
t:rose-suite-hook: more job log rsync tests.

Test with host with/without shared $HOME.
t:rose-suite-hook: add configuration example.
t:rose-suite-hook: more tests.

Also minor change to the settings for configuring these optional tests.
Merge pull request #749 from matthewrmshin/t-skip

test-battery: configurable skip