Drug casebook price effect

I have been meaning to contribute to this project for a while so I figured here would be a good place to start. I have seen a lot of messages and discussions about how reputation is affected by the price of cures so I have started implementing this feature. (It is listed here: https://github.com/CorsixTH/CorsixTH/wiki/Programming-Ideas#drug-casebook-price-effect)

When the user INCREASES prices to large amounts; they will lose rep. Likewise, when a user DECREASES their prices then they will gain reputation. In addition to this, I have also added a new game message for the advisor that tells the user that they can increase their reputation by lowering costs in the casebook (this message appears when they have low rep)