Updated sales and prices display message.

Rewritten chat format for prices.
[FEATURE] Added an option for sales to choose whenever a sale is generic or not. This option is -g and must be just after sale percent. When a sale is generic, the system will not check data and metahash of the object when looking for sales.
[CODE] Added a method in Price for printing its easy name (can be everything, this is good for adding custom names derived from book titles or modified names. The default value is material name as usual).
[Bugfix] Fixed array out of bounds in pager in certain situations.