add GitHub downloader, fix yyjson helper missing break, hide popup list when out of focus

assets/romfs/github/sphaira.json

@@ -0,0 +1,9 @@
+{
+    "name": "sphaira",
+    "url": "https://github.com/ITotalJustice/sphaira",
+    "assets":[
+        {
+            "name": "sphaira.zip"
+        }
+    ]
+}