Add passthrough methods in index.cocoascript

[menzow]

Hey,

Figured out a solution for the issue discussed here: https://github.com/tylergaw/day-player/issues/37

Apparently in recent updates sketch only searches the script file for the handler method specified in manifest.json Because all handlers were imported your plugin wouldn't run consistently.

I prefixed the handlers in manifest.json and pass them through in index.cocoapods to the correct methods. For me this fixed the problem.

Hope this helps someone. Great plugin 👍

[tylergaw]

Hey Thank you for the PR @menzow. I've been away from this project for a bit so it might take me a couple days to get back here, but didn't want to totally leave you hanging