Better Placeable Sell Prices

This script gives the player better prices when selling a placeable.
There is a grace period of 1 month when placing/selling a placeable.
If the placeable is sold within 1 month you will get 100% of the placeable cost back.
After 1 month the price will reduce to 80% of cost and then reduce every month after that (like base game).
You will not be refunded landscaping costs.