Added settings for HTTP audio stream,

[bretello]

This pull request applies changes based on anthonygclark's codehttps://github.com//pull/123, which enables basic support to http streaming in ympd. This patch implements:

1. Change settings of the audio stream server/port in the settings page
2. Store settings in a cookie

[bretello]

Sometimes the httpAudioStream gets stuck and one has to reload the page to get it working again. 3d8c218 was meant to fix this.
Should be able to fix issues by looking at this:
https://developers.google.com/web/updates/2017/06/play-request-was-interrupted