* lib/ur: Implement crash (panic) reporting (fixes#959)
This implements a simple crash reporting method. It piggybacks on the
panic log files created by the monitor process, picking these up and
uploading them from the usage reporting routine.
A new config value points to the crash receiver base URL, which defaults
to "https://crash.syncthing.net/newcrash" (following the pattern of
"https://data.syncthing.net/newdata" for usage reports, but allowing us
to separate the service as required).
The directive lives in its own isolated scope (where we put the visible() function). The stuff transcluded into the notification directive lives in the root scope and doesn't have access to the directive scope. Hence we cannot call dismiss() from inside the directive.
Similarly, config does not exist by itself in the directive scope, we need $parent to access the root scope.
Reference: https://docs.angularjs.org/guide/directive#isolating-the-scope-of-a-directive
How this worked before is a mystery. My guess is Angular bug with directive scope that was fixed in 1.3. One possibility is that transclude plus scope: true (which doesn't make sense as that is supposed to be an object) resulted in the root scope being used in the directive itself. This would then "work" as long as there is only one notification, as visible() and dismiss() would then be registered on the root scope, thus accessible from within the notification but also overridden by any notification rendered.
