Awesome unexpected features #TrainsInMotion #Traincraft (1.7.10 rewrite)

- Multiple passengers finally works now, and it's generic so it can be used in trains and rollingstock. This brings in some great ability for features like street cars and other trains/rollingstock that are more than just for passengers.
Still needs some refining, but the important and difficult stuff works. Finally I can start to make some real progress again.
Now of course the bad news, as I have stated before, only the first rider is saved, so if you are not the conductor/driver and you log out, you probably won't re-mount it when you log back in. This will be fixed in 1.9+ but theres nothing more I can do for this in 1.7.10 due to forge limitations.

- Fixed some improper tick rates for entities.
- Added a static null render to clean up the code and hopefully dramatically improve performance for non-rendering entities.
- Fixed up the entity registry a little bit.
- Added the starting stuff for a key item to allow people to give use of locked trains/rollingstock to specific people. This same code should also be able to work for tickets as well.

Alright, now for the part that's actually related to the clickbait title:
I've also come up with some sweet ideas for boxcars and hopper cars. I'll get into more detail with this later, but for now I'll say this: Most of them will have room for a logo on the side, which actually displays the items from a player-designated whitelist.
I'm also gonna see about adding the data to support things like walia to show it as well. And since I'll probably be knee deep in their API, I'll try and do the same for tanker cars.
I'm also gonna look into support for OBJ train models in the rewrite... Again.