v3.1: reverted back to remote config file.

This is the best version for 1.7.x because it includes back the remote cape config file. In the last version I non-thingingly removed that feature, but it was not practical to leave it that way. Please use this version over v3.1. The config file goes like this.

{
    "capeConfigUrl": "http://example.com/capes.json"
}

Note that in the past, the key was capeTxtUrl. Now it is capeConfigUrl.