Docs: distinguish between older and newer versions of angular for $bindings

[caitp]

Legacy Angular would require methods like ProtractorBy#repeater#column("{{binding}}"). Now, the interpolation delimiters aren't included, and cause failures if they are included. I can't recall which version / sha this changed in, but it's probably a good idea to document it.

[juliemr]

Absolutely. Maybe something in the Angular 1.3 migration guide?

[caitp]

I was thinking it would be more the api docs themselves, since those are what people tend to look for when they're new to a tool, rather than migration guides.

[juliemr]

Sorry for the delays here. Documented in Protractor's API docs, and linked a PR to update the migration docs for Angular 1.2 -> 1.3.

[juliemr]

Migration guide also updated!