New controls, trouing rails, various patches

[Kilarin]

New Controls:LEFT or RIGHT to switch track at junction
DOWN for hand break
JUMP lock the users view to the view of the cart
SNEAK unlock the users view from the cart
Touring Rails: Try to maintain a speed of 4.5
Chat notification of controls when cart is placed
Track rail count in debug.txt
punch by driver patch from spillz (Lets a user start a cart they are riding in)
get_voxel when hit ignore patch by minermoder27 (helps avoid occasional random stops by the cart when the engine doesn't load the next rail)
searches further up and down for rail when cart falls off rails in order to avoid cart getting stuck above or below rails. This seems to eliminate the problem of carts getting stuck several nodes above or below the rail.

I haven't been able to reproduce the "sudden reversal" problem reliably enough to try and patch that yet.

There are some spacing and comment changes in here that happened as I was trying to figure out the code, none of that is important and if they annoy you can be removed.

I'm new to Lua and minetest, so do not hesitate to critique or correct any coding errors I've made.

The deeper I get into the carts code, the more I realize how awesome and complicated the original mod is. Thank you for considering these changes!

[LotekHeavy]

I used your patches and my server crashed after a while. I have long rails with many up&downs.. a few carts running around... and suddenly I got this error message on the server: https://gist.github.com/LotekHeavy/725fd76cd7a4ce5f8073

Till know I couldn't reproduce this, sorry.

[sofar]

There's some good stuff in this patch series but it's combining multiple things into one large patches.

Can you split up your commits so it's easier to merge/review parts of it?

e.g. the part where the player can punch the cart while riding the cart should just be a single commit.

split out the whitespace cleanups into a separate commit

Add the new nodes and craft recipes in a separate commit.

Obviously this needs rebasing, otherwise it's not going to get merged.

[Kilarin]

sofar thank you very much for your comments. When I did this, I hadn't ever worked on a collaborative git project before, so I hadn't even considered separating my modifications into smaller bite-size chunks so that they would be easier to process for pull requests. Makes perfect sense. Sometime when I get time I will consider going through and rebasing this. thank you.