Do not attempt to copy if there aren't any copy targets

Author: Demoli

src/Plugin.php

@@ -51,7 +51,11 @@ public function copyPackageFiles($event)
                 $toCopy += $package->getExtra()['copy-file'];
             }
         }
-
+        
+        if(!count($toCopy)) {
+            return;
+        }
+        
         $this->validatePaths($toCopy);
 
         // add our pacakge copy config to the root package config, so that slowprog can find it
@@ -78,4 +82,4 @@ protected function validatePaths(array $paths)
             }
         }
     }
-}
+}