Add Analyze API to NS

This adds an empty API.
In a next CL I will separate the noise estimation from the Process API and fill this function.

BUG=webrtc:3811
R=bjornv@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/23599004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7218 4adac7df-926f-26a2-2b94-8c16560cd09d