Set example updated syntax

[kmarekspartz]

This is a rebase of #30, and could be part of #86.

As mentioned near the end of #30, I should be adding tests and documentation. I'm not expecting this to be merged until then; I just wanted to get the syntax caught up.

[munificent]

Style nit: how about making this a one-liner:

if (element == item) return true

I like omitting the {} for if (in both C and Wren) as long as the entire thing fits on one line and there's no else clause.

[munificent]

Oh, yeah! I forgot all about this. I tend to go through periods where I cycle between side projects and I put Wren down for a while.

I like this example. Added a few comments. As you noted, some documentation and tests for contains will be good, but otherwise this looks rad.

Once we get maps in the language, I think that will imply more comprehensive support for hash codes. At that point, it will probably make sense to revise this. But until then, this is groovy.

[kmarekspartz]

I see you merged this, but I was still working on it! I'll have a follow-up with some tweaks soon.

[munificent]

Oops! Feel free to send me your tweaks. I was maybe a little overeager to get to zero open pull requests. :)