Add a basic frontend for experimentation

[Plecra]

Hiya! Cool language you've got here 😄

When I just cloned the repo, my first thought was cargo running the compiler to play around with it a bit. I wound up finding the frontend implementation in aspen and thought it'd be nice to make things easier for future curious peeps

[Plecra]

Oh and you can take this as a test that everything runs on Windows no problem!

[slightknack]

Hiya! Cool language you've got here 😄

Thanks!

When I just cloned the repo, my first thought was cargo running the compiler to play around with it a bit. I wound up finding the frontend implementation in aspen and thought it'd be nice to make things easier for future curious peeps

Yeah, this is generally an issue people who are getting started with Passerine run into. Currently, the way I play around with Passerine during development is through the snippets test folder. This, however is less than ideal.

As mentioned in #34, the lex, parse, ... pattern is pretty common when embedding Passerine. I think we should factor a number of helper functions out into lib.rs, then use those for running.

I'm going to merge this PR now; we can most likely simplify it later once the helper functions are implemented. (Oh, and I'll add that it works on Windows to the readme 😉)

Thanks a million!