Updated log targets to use in memory storage

@ejsmith thoughts? This will only happen if you specify a server url or
api key.

Author: niemyjski

Source/Platforms/Log4net/ExceptionlessAppender.cs

@@ -14,6 +14,7 @@ public override void ActivateOptions() {
                 _client = new ExceptionlessClient(config => {
                     config.ApiKey = ApiKey;
                     config.ServerUrl = ServerUrl;
+                    config.UseInMemoryStorage();
                 });
             else
                 _client = ExceptionlessClient.Default;

Source/Platforms/NLog/ExceptionlessTarget.cs

@@ -26,6 +26,7 @@ protected override void InitializeTarget() {
                 _client = new ExceptionlessClient(config => {
                     config.ApiKey = ApiKey;
                     config.ServerUrl = ServerUrl;
+                    config.UseInMemoryStorage();
                 });
             else
                 _client = ExceptionlessClient.Default;