Switch skyline to GIF and add plugin_skyline_compatibility option (#198)

source/plugins/skyline/metadata.yml

@@ -29,10 +29,16 @@ inputs:
     max: 120
 
   # Image quality
-  # Note that it significantly increases output filesize (up to a few Mb) which can cause render/loading issues
   plugin_skyline_quality:
     description: Image quality
     type: number
     default: 0.5
     min: 0.1
-    max: 1
+    max: 1
+
+  # This uses CSS animations instead of GIF to support a wider range of browser like FireFox and Safari
+  # Using this mode significantly increase file size as each frame is encoded separately
+  plugin_skyline_compatibility:
+    description: Compatibility mode
+    type: boolean
+    default: no