Update to PureScript `0.15.0`

[JordanMartinez]

I can help out with this, but since the bindings are code-generated, I'm not sure what's the best way to do that.

Still, the bower.json file and PS deps in package.json are easy to update via update-bower-json-release-versions.txt

jq --from-file update-bower-json-release-versions.txt bower.json > bower.json.tmp && mv bower.json.tmp bower.json

[JordanMartinez]

Oh wait. Only one file is codegen'd.