Fix build warnings

Logging/MemoryLogger.cs

@@ -62,7 +62,7 @@ public class MemoryLogger : LoggerBase
                     ret.Add(_logMessages.GetValueAtIndex(_lastLogMessageIndex + retIndex).ToString());
                 }
             }
-            catch (NullReferenceException e)//Called when LogMessage has not finished writing
+            catch (NullReferenceException)//Called when LogMessage has not finished writing
             {
                 break;
             }

Tranga/MangaConnectors/MangaConnector.cs

@@ -225,7 +225,7 @@ public abstract class MangaConnector : GlobalBase
             }
             if (progressToken?.cancellationRequested ?? false)
             {
-                progressToken?.Complete();
+                progressToken.Complete();
                 return HttpStatusCode.RequestTimeout;
             }
             progressToken?.Increment();

Tranga/Server.cs

@@ -52,7 +52,7 @@ public class Server : GlobalBase
                 });
                 t.Start();
             }
-            catch (HttpListenerException e)
+            catch (HttpListenerException)
             {
                 
             }