convert session to string if object is passed into generate token
convert session to string if object is passed into generate token

mpaniotov/Opentok-Ruby-SDK,brando10/Opentok-Ruby-SDK,brando10/Opentok-Ruby-SDK,HomeStayTravel/Opentok-Ruby-SDK,opentok/Opentok-Ruby-SDK,opentok/Opentok-Ruby-SDK,thepatrick/Opentok-Ruby-SDK,brando10/Opentok-Ruby-SDK,thepatrick/Opentok-Ruby-SDK,HomeStayTravel/Opentok-Ruby-SDK,aoberoi/Opentok-Ruby-SDK,aoberoi/Opentok-Ruby-SDK,HomeStayTravel/Opentok-Ruby-SDK,mpaniotov/Opentok-Ruby-SDK,mpaniotov/Opentok-Ruby-SDK,opentok/Opentok-Ruby-SDK,thepatrick/Opentok-Ruby-SDK