Add missing scope conversions
Move print_output to new Machinery::Ui class

We wanted to add the conversion method for internal to cli data to its
own class.
Since the method print_output in output.rb falls into a similar
category  it was moved to the new class.
Add CLI methods to convert scope names

Since scope names are now stored with an underscore internally we need
to convert them in both directions.
Both methods accept a string or an array and return an array because
the common use case is to have a list of scopes.
Remove Cli.cli_to_internal_scope_names

Since the method was only used in two places of one method it is not
really necessary.
Switch scope name conversion to internal_scope_list_to_string()

Replace Cli.internal_to_cli_scope_names by
Ui.internal_scope_list_to_string.
Merge pull request #69 from SUSE/fix_missing_underscore_conversions

Fix missing underscore conversions