Open
Description
We need an easy way for api.dartlang.org users to switch from the stable channel to the dev channel.
A simple way to do this would be to somehow stick a link on the homepage to https://api.dartlang.org/dev.
A more complex way to do this would be to have a version switcher on every page that tries to take you to the equivalent page in whichever version you select: stable or dev or be.
The sooner the better, since dartlang.org is already on Dart 2. (dartlang.org does take you to the dev version of API docs, but that doesn't help people who type in api.dartlang.org.)
I'll be happy to help with the words, but I couldn't figure out how to implement it myself.
/cc @kevmoo