Add old API docs

[tecnoloco]

I could not find old API docs, even in web archive. I think that we need this to be available because some of the most used generators, like angular-generator (developed by Yeoman Team), are written with old API and if someone wants to modify them to fit some personal workflow is dificult to guess what to use in order to perform certain task if we don´t count on this.

[mischah]

Duplicates yeoman/yeoman#1485