Proposal: Optional Packages

[brunoalano]

I think that we should allow some sort of optional packages, where in one way we will be able to import a lot of packages into Lambda [see #37], and lambda-packages will be thinner.

Extra Packages

[Miserlou]

The issue is that I think I would want the opposite of this behavior, so that lambda-packages is still fat, but installing lambda-packages[numpy] will install only the desired package.

[Miserlou]

I don't know if that's currently possible.