Added huge ship sections, cleaned up whitespace

@geordanr @voidstate @fab7431 

I've added support for huge ships as discussed to the spec text and to the custom validation function. I haven't updated the schema.
I moved some of the less-critical sections like `vendor` and versioning to the bottom of the README, so that people get to the interesting stuff more quickly.

I'm going to assume that a lack of feedback after 72 hours-ish indicates agreement, generally. That's a rough distillation of how Apache handles commit rights on projects, and while I think that we need a system for how to handle people being away, etc., I don't think we need to be super formal.