costScale added.

Adds a field which can be added in the faction/class' shared file (.costScale) which scales the business menu item costs by the amount set. Default is 1 (no change).
Updated with server-side stuff

And a minor change to client-side getting cost of item.
fixed some derps from c/p'ing code
Merge pull request #169 from CloudSixteen/costScale

costScale added.