Comments on the available extension list and the extension getting method

Clarify that they're for server side only.

Release note: n/a

R=ricea@chromium.org

Review URL: https://codereview.appspot.com/11089043

git-svn-id: http://pywebsocket.googlecode.com/svn/trunk@778 4ff78f4a-9131-11de-b045-6380ec9940d4
Log when get_extension_response is called on inactivated processor

Release note: n/a

R=ricea@chromium.org

Review URL: https://codereview.appspot.com/10921044

git-svn-id: http://pywebsocket.googlecode.com/svn/trunk@779 4ff78f4a-9131-11de-b045-6380ec9940d4