Add explicit order hints to YAML SQL definitions

[wolfsage]

This shuts up SQL::Translator::Parser::YAML warnings...

[rjbs]

I look at this and think two things:

1. thank goodness to have an end to warnings
2. I am going to screw this up when I change something later

Can we use a sequence instead of a mapping for these fields, so they're naturally ordered?

[wolfsage]

Hrm, how do you envision the sequence looking?

Something that's interpolated and increments?