Work on plugin mechanism

Context actions have become normal actions in the pluginwidget so the widget knows abot them and
can easily do things like enable/disable.

pglab/plugin_support/LMainWindow.cpp

@@ -99,7 +99,7 @@ void LMainWindow::addModuleMenuActions()
 	auto reg = PluginRegister::getInstance();
 	auto mods = reg->modules();
 	for (auto && mod : mods) {
-		auto items = mod.second->menuActions();
+		auto items = mod.second->staticActions();
 		for (auto && item : items) {
 			addMenuAction(item);
 		}