Patch notes for v0.7.1c

* Fixed regression causing train track no-stopping zones being incorrectly removed from intersections during direction flipping. To prevent trains blocking each other, ensure that all overlapping tracks (denoted with yellow arrows on track direction overlay) are marked as no-stopping zones (red markers).
* Fixed schedule conditions being incorrectly combined when using OR and AND operators.
* Level crossings are now marked as no-stopping zones by default.