Run Eve examples as part of automated tests

[cmontella]

Currently, CircleCI runs npm test as part of the automatic push tests, but it should also check to make sure all the examples compile fine. I'm not sure how we can actually make the examples unit tests, but they should always compile. If they don't, this indicates either a problem with the example or the language.

[cmontella]

To be clear, I'm talking about compiling the tests to make sure they are at least valid Eve programs. There's an additional question about testing in general. Right now, writing tests requires writing Eve code in typescript files, which makes adding more tests tedious and error prone.