set jsxFragment option from CLI

At the moment it is not possible to specify the `jsxFragment` option when run Bublé from the command line.
It is easy to add a `--jsx-fragment` flag, since support for this feature is already in place

Start at the command-line option parsing entry point and trace how the existing jsxFragment option is passed into Bublé. Add the --jsx-fragment flag and verify that command-line compilation uses the requested fragment setting, including an appropriate CLI test if the repository has one.

Written by the indexing model from the issue text.