Fine-tuning shooting direction with SHIFT+Mouse drag

Control (shooting direction) needed rework.

• I added a fine-tuning mode: hold SHIFT and drag the mouse for fine-grained change of shooting angle
• I added handling for clicking on / dragging over water - this now changes the shooting dir, too (that was not the case before)
• Estimated ball collision is now always calculated - even when the collision is much farer away. This avoids former cases where you thought the ball would collide with an edge but actually the collision calculation did stop too early there.