Render notifications in junks

Fixes #234.

pageAction/pageAction.js

@@ -185,14 +185,26 @@
 		browser.runtime.onMessage.addListener(function(data){
 			if (Array.isArray(data["canvasBlocker-notifications"])){
 				message("got notifications");
-				data["canvasBlocker-notifications"].forEach(function(notification){
+				const notifications = data["canvasBlocker-notifications"];
+				let i = 0;
+				const length = notifications.length;
+				const tick = window.setInterval(function(){
+					if (i >= length){
+						window.clearInterval(tick);
+					}
+					else {
+						for (var delta = 0; delta < 20 && i + delta < length; delta += 1){
+							let notification = notifications[i + delta];
 							verbose(notification);
 							notification.url = new URL(notification.url);
 							domainNotification(
 								notification.url.hostname,
 								notification.messageId
 							).addNotification(new Notification(notification));
-				});
+						}
+						i += delta;
+					}
+				}, 1);
 			}
 		});
 		message("request notifications from tab", tab.id);

releaseNotes.txt

@@ -14,6 +14,7 @@ Version 0.5.3:
 		- detection if the options page was displayed in a separate tab did not work reliably
 		- popup text not readable in some dark themes
 		- display conditions for notification settings
+		- page action not useable with a lot of notifications
 	
 	known issues:
 		- if a data URL is blocked the page action button does not appear