RFC: blueprint-sortinghat and blueprint-create --diff

[Richard Crowley]

Greetings blueprinters,

We've got a couple of new features kicking around and would really
love some feedback. These are both at a high level about bringing a
bit of modularity to blueprints, so they're not an all-or-nothing
description of a system.

First up, is the to-be-renamed blueprint-sortinghat command, for
interactively splitting one blueprint into two:
https://github.com/devstructure/blueprint/pull/93

Second is a new option to blueprint-create, --diff, which accepts the
name of a blueprint to be subtracted before committing:
https://github.com/devstructure/blueprint/pull/94

I hope both of these commands, in some form, will be the base of the
Blueprint 3.2 release.

Check 'em out!

Richard