Make imports optional

[hanoii]

I would like imports to be defined but that they wouldn't err if the import file doesn't exist or it's empty.

[ocean]

Hi @hanoii thanks very much for this! Yes, I'm very happy to get contributions and pull requests from you, that would be great.

I'm nearing the end of a long a complex website release at the moment, so forgive me if I don't get a good look at this right away, but I do have some time planned soon to do some more things with ahoy.

Do you think you could write a test to demonstrate this feature working? You can write one in Go or bats, whichever works for you.