I found this blog entry tonight and tried it and it works. The instructions refer to VS2013. For those trying this in VS2015, I had to create the "cert" folder as mentioned below. Also, these instructions mention a "windows8" folder. In VS2015 the two platform folders for Windows are "windows" and "wp8" (under the other "res" subfolders, anyway). To err on the side of caution, I created those two folders, plus a "windows8" folder. I then created the xml file as specified below, edited it, and copied it to all locations.
When I built, my generated appxmanifest reflected the updated values.
http://sonyarouje.com/tag/cordova/
Create a Package.appxmanifest file under res/cert/windows8. Create a windows8 solution folder if not exist.
Open the project folder and go to bld/windows-AnyCpu/Debug and open AppxManifest.xml in notepad, copy the content and paste it in the above Package.appxmanifest file.
Double click on Package.appxmanifest file then goto Capabilities tab and choose ‘Private Networks (Client & Server)’.
Save it and run the app again, this time it worked