Refactor TrainCar part 1

[twpol]

Refactor TrainCar

Roadmap: https://trello.com/c/rA9gu11Q/526-refactor-traincar-to-simplify-inheritance Discussion: http://www.elvastower.com/forums/index.php?/topic/36050-refactor-traincar-to-simplify-inheritance/

For the first refactoring I have chosen a couple of small parts: animated couplers and animated air hoses

Statistics

These statistics will be included with each refactoring part to demonstrate the improvements to the code (less code, same or more comments), which have been calculated using the scc (https://github.com/boyter/scc) tool

Bytes	Comments	Code	File
+756	+5	+7	Source/Orts.Parsers.Msts/STFReader.cs
+160	0	+2	Source/Orts.Simulation/Orts.Simulation.csproj
-988	+1	-28	Source/Orts.Simulation/Simulation/Physics/Train.cs
+1,238	+16	+17	Source/Orts.Simulation/Simulation/RollingStocks/Coupling/AnimatedAirHose.cs
+1,129	+16	+15	Source/Orts.Simulation/Simulation/RollingStocks/Coupling/AnimatedCoupler.cs
-3,783	+4	-52	Source/Orts.Simulation/Simulation/RollingStocks/MSTSWagon.cs
-1,847	0	-37	Source/Orts.Simulation/Simulation/RollingStocks/TrainCar.cs
-385	0	-7	Source/RunActivity/Viewer3D/RollingStock/MSTSWagonViewer.cs
-3,720	+42	-83	Total

Note

I am starting the PR with the not-for-unstable label because it will likely conflict with #569 until that one is merged

[cjakeman]

I am starting the PR with the not-for-unstable label because it will likely conflict with https://github.com/openrails/openrails/pull/569 until that one is merged.

#569 was merged a few days ago :-)

[cjakeman]

For the first refactoring I have chosen a couple of small parts: animated couplers and animated air hoses

Comparing "before" and "after" is going to be interesting. Hoping to see see what professional practice looks like, so thanks for sharing.

[twpol]

Comparing "before" and "after" is going to be interesting. Hoping to see see what professional practice looks like, so thanks for sharing.

This is simple extraction of repetitive data, but things will get more interesting with time :)