Bugfix update 1.1 - Gravel

Fixed two bugs pertaining to the gravel verge on the side of the road:

• Previously, crashing on the gravel once prevented you from ever being able to go on the gravel again without instantly crashing. You will now get the customary number of allowed gravel turns every time.
• The bus would stay stationary if you attempted to move onto the gravel from one tile above or below it if you were also scheduled to veer in that direction on the same turn. Now you will move onto the gravel as normal.