Patch: simplified realistic acceleration

[kaan]

You might want to consider if you really meant that the patch was made for r1051?
I think that it might be safe to bet that you really meant 10051

[Zojj]

lol thx

[Zojj]

I'm gonna split up my acceleration patch, cuz it has some good parts and some controversial parts.

This patch improves the curve, depot, and station speed limit code. The behavior is identical except for one difference: Trains are no longer slowed by successive S bends.

I have also left in the code (but commented out) 3 options that I think make sense:
-Trains' max speed is limited while inside a station, the same manner as while inside a depot but faster.
-Faster railtypes have faster speedlimits while inside a station; a monorail train can enter faster than an electric train.
-Faster railtypes have faster speedlimits while inside a depot. Maglevs enter at 151kph.

The current code is obfuscated, I really want to fix it. =)