Add better train failure messages

[DeadMG]

TL;DR

Sometimes, things with trains don't work, but the game doesn't tell you why. Add explainers for a few more cases.

What ?

There's three situations where the game can do weird things but not tell you why.

• Fluid pump not working because wagon not straight
• Fluid pump not working because wagon misaligned (not automatic at a station)
• Interrupt not taken

Therefore I'd suggest that if a fluid pump is pointing at a stopped wgaon, the game should display a symbol and error indicating why the pump won't activate. Additionally, if a train is stopped, the player can mouse over an interrupt and see which condition failed, or possibly click on it or see a message under the interrupt.

Why ?

Encountering these failure cases is quite frustrating and makes the player think the game is broken when it's maybe not. I'm honestly still not sure if interrupts are buggy or if I'm bad at using them.