BUG FIX : You can play successive levels
PLUS : Stuff to make it work as an .exe
PLUS : Ability to sell items

* selling items restores half of the price you paid for them.
PLUS : Pause/Resume resource gathering

* you can pause resource gathering ( and inheritenly, pollution raise)
by stopping a power plant
* to resume it, you have to pay the price you paid for it divided by 4
BUG FIX : Selecting buildings doesn't stack GUIs

* Now when you select a building, the gui for all the buildings is
erased and the gui for the new building appears