Update psd.js entry to point to dist/ instead

[MgenGlder]

Summary

• Fixes Update package.json main entry to point to dist/psd.js #233.
• We want to update the main entry in package.json to use the dist compiler version of psd.js
• Also makes the project compile as a standalone package, instead of requiring the importer to a coffeescript compile build step in their pipeline.

Background

N/A

Acceptance

• Make sure it still works.

[MgenGlder]

Verified that it still works, tested and everything seems well and dandy. This should be a great value add to making the project easier to work with.