Version 4.0 released

Greymarsh is heavily inspired by classical, old-school gamebooks from the eighties and nineties, with their simple battle systems based on dice rolls. With this update, Greymarsh goes all the way and makes the mechanics of combat explicit with dice rolls on screen, showing more clearly where randomly generated numbers play a part in the flow of battle. Some other graphical flourishes are introduced as well, like red bars showing the remaining hit points for player and opponent alike. As usual, a few minor bugs and typos have been removed.