tests: Fix some CLI tests. Add auto-stripping of newlines in the CLI output for tests that use the simple YAML string value for the expected output. Also, fix `showconfig` test to expect a root URL with a trailing slash.

[pytest]
norecursedirs = .* _darcs CVS .svn .git .hg *.egg-info dist build bower_components node_modules venv tmp* _cache {args}