Basic support for cues

[Charles]

I haven't had a chance to work on cues in earnest, but I snuck in support for using "cue" instead of "def" on methods like "init" and "equals". So for example:

class Point

    cue init
        .init(0, 0)

    cue init(x as int, y as int)
        _x, _y = x, y

This gets us closer to the final form of Cobra syntax and the 0.9 release. All the Samples and HowTo's are updated in the repository.