[swift-evolution] RFC: Swift Package Manager -- Editable Packages Proposal

[Daniel Dunbar]

I am proposing we change the behavior for iterative development of a group of packages. In particular, we will change the default location to which package dependency sources are cloned, the package managers behavior around those sources, and add a new feature for allowing iterative development. These features are tightly interrelated, which is why they are combined into one proposal.

Proposal here:
  https://github.com/ddunbar/swift-evolution/blob/dca2f84ff9dd910c4d8c648da3a3f727ed918274/proposals/NNNN-swiftpm-package-edit.md

Feedback welcome!

 - Daniel