New vehicle RV take two

While looking through the pull requests, saw there was a pull for an RV
that seemed kinda abandoned #2053 .  It looked like a really cool idea,
just needed to be finished, the design was based on original Cataclysm
and didn't work in DDA.  Seeing as there had been no activity in two
weeks, I thiugh I'd try and complete it.  So far I think I have the
design in veh_typedef.cpp fixed (bunch of misc. errors), but I'm not
sure how to add this to spawn lists.  Anyone know how vehicle spawns
work?

PS - I know this isn't my idea, it's just no one answered my comments on
the original pull and this is too cool to just let die.  If I should
have made a pull off the original request or whatever please tell me and
I'll take this down.  I don't want it to seem like I'm stealing people's
work.
Fix unknown characters in diagram
Remove duplicate phase entry for gasoline
fix RV assemby order (the internal door made -2,0 a bad place to extend frame)
Fix heavy fletched field point arrow weight
Fix broken recipe skills
Merge pull request #2 from atomicdryad/RV_assembly_order

Rv assembly order fix by atomicdryad
Convert weights to fix point precision if needed
Part 1
Update to mainline
New vehicle part (underbody wide wheel)

Seeing as nobody wants a campervan with huge holes in the roof, I've
made a new vehicle part: underbody wheels.  For an extra point of
required skill, you can install wheels UNDER your vehicle instead of on
the sides.  This allows you to install interior parts (like roofs) on
the same tile as your wheels, so you don't have big holes in your
ceiling if you want to mount wheels somewhere other than the edges of
your vehicle.  This started as just an addition to get the RV working,
but I think this will actually be a significant addition to vehicle
crafting as a whole.  Now you can make larger vehicles (like moving
houses!) and be able to have wheels in the middle without screwing
things up.  This only adds the wide wheel (underbody) for now; I made it
as a proof of concept to see if this would work.  I'll make the rest of
the wheels tomorrow.

Note - For some reason, this has changed the size of the wheels
displayed in game.  I gave it same wheel width, only changed damage (to
match frame damage, which is essentially what this is).  Not sure what's
causing this, anyone have any ideas?  Also, in a test build the size
seems to change based on multiple wheels next to each other, wierd.
New sword (zwiehander)

Built from the suggestions of whitelight04 and others here #2349, the
zwiehander is a large, two-handed sword with WIDE, WBLOCK_1, and BRUTAL.
It shows up in itemgroups.json in medieval and pawn fairly rarely.  If
you have any balance suggestions, please comment!

Tested and works
Add spawns to mapgen.cpp, Cleanup vehtypedef.cpp

Okay for now I'm going to just fit this in with the current vehicle
system instead of reworking half the game.  Added the RV to mapgen.cpp,
it rarely shows up with the broken vehicles on roads, and will very
rarely be in a parking lot.  Changed all the floor trunks to aisles,
still has 4 trunks so I think it's good for storage.  This still uses
the underbody wide wheels, which is a new part but it doesn't change any
other parts so I think it's okay.
I'd like this to have a chance to spawn at hotels, but I'm not sure how
to do that so for now it doesn't.  If anyone has any tips on that let me
know!
Uncapitalize names and color change
Fix stupid spelling mistake (thanks CIB)
No. 9 takes 4 skill instead of 5
more tweaks
Change bionic letter allocation, should be possible to get up to 94 bionics

Fixes #2003
Part 2
Fix readme (hopefully)