Heroic gog support (#72)

* Only use icons if they exsists

* Initial gog support from heroic

* Find gog linux games

* Update readme to include gog games

* rename appName to app_name

src/heroic/heroic_game.rs

@@ -13,6 +13,8 @@ pub struct HeroicGame {
     pub launch_parameters: String,
 }
 
+
+
 impl HeroicGame{
     pub fn is_installed(&self) -> bool{
         Path::new(&self.install_path).join(&self.executable).exists()