Allow list items to be targeted by index

[timkendrick]

This allows templates to access list items by index, as discussed in janl/mustache.js#158.

Example usage: {{#myList.0}} {{/myList.0}}

[xxgreg]

Thank you!

I added some tests. Feel free to flesh these out.

e9c2bb7

Also - should this throw a RangeError when the index is out of range, what do other mustache implementations do? I find strict is usually better, but mustache libraries often seem to prefer lenient handling of errors.

If you're happy with this let me know, I'll push it up to pub.

[timkendrick]

Great, thanks for adding the tests. I was wondering the same thing about whether to throw a RangeError, feel free to modify the code however you want and push to pub. Thanks!

[xxgreg]

Updated to version 0.1.17
http://pub.dartlang.org/packages/mustache