PureScript

I made an attempt at adding support for PureScript to shakespeare-js, but I'm unsure how to go about testing it. I'm still very unfamiliar with Template Haskell at this point. :(

If you have any advice for adding this to the test suite, I'd be willing to give it another go. I tried for quite a while and gave up/realized that I have no clue what I'm doing, but I'm sending what I attempted (in commit 5b9f468).

This is very heavily based on the Roy module, with the temporary file code taken from the TypeScript module.