Pushover: rewrite for non-blocking HttpUtils

[System]

Pushover: rewrite for non-blocking HttpUtils

Pushover: rewrite for non-blocking HttpUtils Rewrite for Non-Blocking HttpUtils - much more readings - Support for emergency callback via push - Support for supplementary URLs incl. push callback  (e.g. for priority < 2) - Added readingFnAttributes to AttrList - Added support for HTML formatted text - Added user/group token validationView Changes

Source: Pushover: rewrite for non-blocking HttpUtils