Update version from 0.7.5 to 0.7.6
Update version from 0.7.5 to 0.7.6

TBR=tyoshino@chromium.org,bashi@chromium.org

Review URL: https://codereview.appspot.com/6300090
google/pywebsocket,googlearchive/pywebsocket,googlearchive/pywebsocket,GoogleChromeLabs/pywebsocket3,GoogleChromeLabs/pywebsocket3,google/pywebsocket,GoogleChromeLabs/pywebsocket3,google/pywebsocket,googlearchive/pywebsocket