added kpm packages folder to list of locations to inspect for vnext

Hope this is ok. If you install K via Homebrew as shown in the instructions here https://github.com/aspnet/Home there is now a central packages folder not under each app as in previous apps that appears in ~/.kpm

See screenshot

![screen shot 2014-08-07 at 14 33 58](https://cloud.githubusercontent.com/assets/105126/3842511/f9791802-1e37-11e4-91de-1a355024a400.png)