Few fixes/improvements

I have just finally gotten round to installing this at ValveTime.net and have made some improvements I think could be in the next release.

1) The installer will no longer give a duplicate column error thanks to a special function which first check if the column exists before attempting to create it.

2) The membercard and other areas listed viewers of the Steam pages as "Viewing an unknown page". I have added this session activity detail. It points to a phrase "checking_out_steam_stats"