Allow multiple arguments in the CLI

[MatthieuBizien]

Fix #19

28 was closed by Github and I can't re-open it

• Allow multiple arguments in the CLI
• Use a more functional style

[mpalmer]

Hmm, #28 is really weird... the GH UI says you closed it, but the reopen buttons are greyed out for me (as I assume they are for you).

Anyway, this PR looks solid. Thanks for the contribution!