PSI calculation tweaks

[fancygama]

Unless it just appears this way, PSI's are currently calculated as the logic of the integer tiers of your top 10 TCIs who've seen the movie. I don't think it would necessarily be excessive to utilize more precise tiers (i.e. if something was rated at the end of tier 10 it could be a 9.1 and etc.). This might make more sense, since the average of the 10 tiers ends up being a double anyway and is converted into a score based on where it is in that specific tier.

Also, I realize that 10 TCI's is usually plenty in terms of precision, but it's still vulnerable to outliers a bit. Maybe the top 20 TCI's could be used, with the caveat that each one's effect on the average is weighted by TCI^-1.

[mpowell]

Thanks for the suggestions! We've got a list of proposals to help refine the accuracy of the PSI, and have added your ideas to that. We're constantly trying to balance performance with accuracy, but there's always room for improvement