plugins: use optional flag to handle background behavior of lua plugins

Old behavior is untouched, but Lua plugins which are using neutrino-lua APi
can manage background behavior of their windows by themselves.
This flag allows more flexibility.


Origin commit data
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Branch: ni/coolstream
Commit: 2029c93f1d
Author: Thilo Graf <dbt@novatux.de>
Date: 2023-01-06 (Fri, 06 Jan 2023)



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This commit was generated by Migit

src/gui/plugins.cpp

@@ -393,8 +393,14 @@ int CPlugins::startLuaPlugin(int number)
 #if 0
 	frameBuffer->ClearFB();
 #endif
-	videoDecoder->Pig(-1, -1, -1, -1);
-	frameBuffer->paintBackground();
+	std::string keep_bg_flag = "/tmp/.keep_background";
+	if (!file_exists(keep_bg_flag))
+	{
+		videoDecoder->Pig(-1, -1, -1, -1);
+		frameBuffer->paintBackground();
+	}
+	else
+		remove(keep_bg_flag.c_str());
 
 	return plugin_list[number].menu_return;
 }