am 4d4ef4e0: am 9762ff45: am c7d1ee8b: docs only. add new Updating Your SDK doc; update the \'android\' tool documentation.

Merge commit '4d4ef4e02e9dd1cc54bf1db19f96adc01508308d'

* commit '4d4ef4e02e9dd1cc54bf1db19f96adc01508308d':
  docs only.