Fixed plugin loading and closing issues mainly on Windows

This fixes #87

source/window.cpp

@@ -552,7 +552,7 @@ namespace hex {
         } catch (std::runtime_error &e) { return; }
 
         for (const auto &plugin : PluginHandler::getPlugins()) {
-            plugin.initializePlugin();
+            plugin->initializePlugin();
         }
     }