Add a .log method for logging stuff to nqpjs.log when the env var NQPJS_LOG is set.
Add a mini-nqpmo (a proper nqpmo will be generated properly in future commits).

The following code works now:
my class NQPMu {
}
my class Foo {
    method foo() {
        say("hi");
    }
}
Foo.foo;