update to previous update

Fixed it so the previous views update their display info after a
committed sell offer
Buy from seller transactions in GUI

You can now buy stocks from a sell offer in the gui from the seller's
market. This completes all transactions on the seller's market side.
Note: I have not added any error feedback messages yet. If a transaction
can't be completed to due a validation failure, nothing will happen. One
validation I added that we didn't discuss - if you have stock's for sell
in the market, you can not sell more stocks for a different price than
what's already in the market. As a side note, we didn't allow for any
way to remove your offers from the gui.