trains

It would be nice to have checkbox in the options to disable the vehicle obsolete date - being able to buy vehicles that are not longer available due to reaching the obsolete date. Thus we could create retro trains, planes, etc. in our games.

Timer 4 is the 40 bit debug timer (as described under section 18.1.3). It's similar to Timers 1-3, albeit without as much "customization" options.

It should be fairly easy to implement:

• Modify the current timer device to use a internal u64 counter for time-keeping
• Create a "wrapper" device which masks masks out any timer registers unavailable on Timer 4
• Update the Ts7200Bus struc