Old cabs, new features

Well I finally got around to adding the rest of the necessary features to control Trains. The changes are generic for all trains no matter what kind of cab, but since we only have the old plug-in ones right now, so I describe the features w.r.t. those.

- Autostop-on-red works significantly differently. The new idea is that if there's actually someone there watching the train controls, don't get in their way at all. However, if the throttle is just sitting there unattended, stop the train before it crashes.

So, it's no longer required to press a specific button to restart your train after a red signal. Simply twiddling the speed knob will make you move again. In addition, there's a delay of 0 to 3 seconds after you get a red before it stops your train to allow you time to twiddle before the autostop. If it's moving faster than around 50%, it stops immediately (Bad operator! You shouldn't be going that fast with a yellow signal anyways!). Below that, the slower your train is moving, the longer the delay is. I'm not sure how this feature will work out, people should try it out and see if it works.

- You can now steal the block ahead of you if it is occupied and unassigned using the '9' key.

- You can now drop the trailing block of the train using the '7' key.

- The cabs now emit irritating noises when your signal worsens to yellow or red or when you press a button whose action is not possible.

The button I previously called "call on" is more properly a "reset" button - its only duty now is to un-FOO your cab.

So, the full list of button actions is: