Add itemized feedback in init

[darkowlzz]

init should have itemized feedback to provide the user information about each direct dependency’s inferred constraint (to be placed in the manifest), as well as precise version information to be placed in the lock for all dependencies.

Example:

Using ^1.0.0 as constraint for direct dep github.com/foo/bar
Locking in v1.1.4 (bc29b4f) for direct dep github.com/foo/bar
Using 1b8edb3 as hint for direct dep github.com/bar/baz
Locking in master (436f39d) for transitive dep github.com/baz/qux

More details in the spec.