quite a few changes here.
removed unused import declarations
the learner environment doesnt expect a toolContentId to be passed via url.
the tool contentId/toolSessionId relationship is assumed to have been establish when the core made the call to createToolSessions()
if no toolSession exist in the table when the learner reaches the activity, the user will see an error screen.
if user in this tool session isnt found, thena new entry is created.
