am a0711e7b: Doc change: Add compatibility article.

Merge commit 'a0711e7b3995f4ae3d8b116030c6b3ed13ad2f99' into froyo-plus-aosp

* commit 'a0711e7b3995f4ae3d8b116030c6b3ed13ad2f99':
  Doc change: Add compatibility article.