Add error handling when checking updates, and remove unnecessary TODO

Core/FormBrowser.cs

@@ -39,6 +39,7 @@ public bool IsWaiting{
         }
 
         public string UpdateInstallerPath { get; private set; }
+        private bool ignoreUpdateCheckError;
         
         public AnalyticsFile AnalyticsFile => analytics?.File ?? AnalyticsFile.Dummy;
 
@@ -247,7 +248,12 @@ private void updates_CheckFinished(object sender, UpdateCheckEventArgs e){
                         }
                     }
                 }, ex => {
-                    // TODO show error and ask if the user wants to temporarily disable checks -- or maybe only do that for the first check of the day
+                    if (!ignoreUpdateCheckError){
+                        Program.Reporter.HandleException("Update Check Error", "An error occurred while checking for updates.", true, ex);
+
+                        ignoreUpdateCheckError = true;
+                        updates.StartTimer();
+                    }
                 });
             });
         }
@@ -329,6 +335,7 @@ public void ReloadToTweetDeck(){
             Resources.ScriptLoader.HotSwap();
             #endif
 
+            ignoreUpdateCheckError = false;
             browser.ReloadToTweetDeck();
             AnalyticsFile.BrowserReloads.Trigger();
         }

Core/Other/Settings/TabSettingsGeneral.cs

@@ -227,7 +227,7 @@ private void updates_CheckFinished(object sender, UpdateCheckEventArgs e){
                             FormMessage.Information("No Updates Available", "Your version of TweetDuck is up to date.", FormMessage.OK);
                         }
                     }, ex => {
-                        Program.Reporter.HandleException("Update Check", "Encountered an error while checking updates.", true, ex);
+                        Program.Reporter.HandleException("Update Check Error", "An error occurred while checking for updates.", true, ex);
                     });
                 }
             });

Updates/UpdateCheckClient.cs

@@ -21,7 +21,7 @@ public Task<UpdateInfo> Check(){
             TaskCompletionSource<UpdateInfo> result = new TaskCompletionSource<UpdateInfo>();
 
             WebClient client = BrowserUtils.CreateWebClient();
-            client.Headers[HttpRequestHeader.Accept] = "application/vnd.github.v3+json"; // TODO could use .html to avoid custom markdown parsing
+            client.Headers[HttpRequestHeader.Accept] = "application/vnd.github.v3+json";
 
             client.DownloadStringTaskAsync(ApiLatestRelease).ContinueWith(task => {
                 if (task.IsCanceled){