Overhaul peerDeps again

[benjie]

Redoing dependencies/peerDependencies around this:

With that being said, Yarn supports "peer dependencies with defaults": if you list a dependency as both a peer and regular dependency, Yarn will use the parent-provided dependency, but will fallback to the regular one if missing. Pnpm supports it too, and I believe even npm supports that somewhat accidentally due to how their "auto-installs" work.

yarnpkg/berry#3710 (comment)

On top of that:

• I've added a pgl binary package with no peerDeps that can be ran through npx in case everything else fails
• I've added a bunch more fwds
• I've revised some of the code to use the fwds

Fixes #411
Fixes #412