Dep: Separate code into subpackage(s)

[sdboyer]

To keep things moving quickly, our initial work on dep clustered everything into a single package. That's not ideal for the long term, though. I can imagine at least two discrete subsystems that need separating:

• Manifest and Locks, plus the txn writer that works with them.
• The analyzer. This is tiny right now, but may get a fair bit bigger over time, especially if we choose to teach it to read data from the existing community tools.

My first instinct is to put these in separate packages, but if we're trying to maintain consistency with how the toolchain does things, it might be better to just put them all in one, non-main subpackage.

[rakyll]

It would be nice to work with lock and manifest files programmatically! Moving things out of the main package is something I am looking for.

[erizocosmico]

Yes, it would be really nice to move everything out of the main package. If no one is on it I can work on it tomorrow. I'd only need to know if I should put everything in one non-main subpackage or go for the multi-package approach.

[sdboyer]

@erizocosmico awesome! i think just one is good to start with. I suspect it'll be as much updating the supporting/CI scripts as it is actually moving code around.

[erizocosmico]

Nice, I'll do it asap.

[sdboyer]

178 is merged, so marking this done. We can make a new issue if we want to further subdivide the primary lib package later.