am 40057ce7: Document that stopPreview is not needed before takePicture.

Merge commit '40057ce749c8c4d274db0352a2af4344bda92dba' into eclair-mr2

* commit '40057ce749c8c4d274db0352a2af4344bda92dba':
  Document that stopPreview is not needed before takePicture.