code review 6406045: gotour: achievement system

gotour: achievement system

Added a simple achievement system to keep new gophers motivated.
The achievement bubbles are displayed on the bottom right corner and
multiple bubbles will stack automatically on top of each other.
You can test this functionality by running the program on slide #14
with an empty localStorage.

This CL only introduces 6 example achievements, but the plan is to
add quite a lot of them. Feel free to propose additional achievements!

[tux21b, 2012-07-14 20:50:44]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go-tour

[adg, 2012-08-27 05:51:11]

Hey,

I did a similar thing here: http://codereview.appspot.com/5652075/

It has a more complex way to evaluate progress, and will check for common errors
and provide hints.

I've avoided responding to this CL for a while because I'm not sure how to
proceed. If we're going to introduce achievements, they should be well-designed
and valuable as a learning tool.

Not saying yours aren't. I just haven't digested your approach yet.

[bradfitz, 2013-06-05 20:52:35]

R=close

I assume this no longer applies.  I think adg still wants to do something like
this eventually, so maybe this could be resurrected.