Basho Eval

This is the parser and evaluator used in the basho project. For documentation
see https://www.github.com/jeswin/basho.

It exports the PipelineError class and the evaluate() function.

Usage looks like this:

``javascript
it(Passes an object to a shell command, async () => {
const output = await evaluate(["{ name: 'kai' }", "-e", "echo ${x.name}"]);
(await toResult(output)).should.deepEqual({
mustPrint: true,
result: ["kai"]
});
});
``

See the
tests
for more examples.