Clone repos instead of fetching individual files

[tj]

Maybe. It would be nicer for local hacking.

[matthewmueller]

It'd also be nice for supporting meta data like config files for linters, e.g. .eslintrc. Do you know how you'd resolve includes for this use case? For example:

include github.com/tj/make/golang

Resolves to:

git://github.com/tj/make

go get must have specific knowledge about how to resolve github.com urls? We could probably copy go get here.