- The `TMoverParameters::derail()` function has been renamed to `::Derail()`, with a capital D.
- All derail events now use that function.
- Simplified and unified the logic behind different derail types.
- The `dtrack_freerail` track type is now slightly increasing the chance of derailing on a tight curve, as it was the intention.
- A new `DerailReason` enum has been created which holds all derail types.
- The `DerailReason` field in the `TMoverParameters` class has been removed.
- This was a transient field which is not necessary anymore.
- The logging functionality as such has been moved from `DynObj.cpp` to `Mover.cpp`.
