Provide examples and thorough docs for ngAria

[caitp]

The documentation for ngAria leaves a lot to be desired --- we need to fill it up with some more content and usage examples so that people can feel confident in trusting ngAria for their accessibility requirements which they are legally obligated to meet (depending on industry).

Lets make these better.

[caitp]

ping @marcysutton could you help with this?

[marcysutton]

Yep! I'm working on a Developer Guide today, actually. When I have the PR ready I'll circle back to this issue.

[caitp]

awesome, thanks!

[petebacondarwin]

@caitp - please don't add more issues to 1.3.2 milestone. Either add it to 1.3.x or create 1.3.3 and add it to that. We want the issues in this milestone to be tending to zero by tomorrow!!

[caitp]

We have a patch for this, we're getting this done tomorrow. Code freeze is tomorrow night.