A post describing what .Net Core provides for configuration managment: IConfiguration in .NetCore.
You have a hierarchical settings provider architecture able to merge mutiple sources. The only drawback: it’s not possible to strongly typed settings.
Seems pretty interresting. You also have in the box ini files, command line, environement variables and the ability to ReloadOnChange for files (through the general Microsoft.Extensions.Primitives.IChangeToken).
Weak documentation and extreme modularity complicate usage (It takes me too long just to find where IChangeToken is) .
This is supposed to be available on .Net 4.5.1 but only in prerelease.