Global install and local install do completely different things #74

Right now global install doesn't seem to do any of the same steps as a local install.

Local install copies specified files into a deps folder and links the ones you specify into a bin folder.

Global install just clones the repo and runs make install(or a different command if you specify one).

If, as a developer, I want to support both I have to either write a standard make install task and have my code be able to handle being laid out two different ways, or I have to write build code that replicates the local install functionality of bpkg but as root in an appropriate global folder.