Moving parser's plugins logic to separated classes

As the title says, this moves all the parser's plugins logic to their own classes.

Each plugin has its own class and communicate with the Parser using a 'bridge' class "PluginHelper".

That way, the parser is only parse and only holds data related to this task, just like the plugins, each plugin is responsible for its logic and its information. All this allows the code to be clearer and better structured.