Avoiding wasting time and ressource when initializing a clip.

When loading a clip, media player was launched in play state, then paused, then unpaused.
Not it's just launched in a play state.
Preloading still use this method, as it's not supposed to play before we explicitly ask for it.

src/Workflow/ClipWorkflow.h

@@ -69,6 +69,7 @@ class   ClipWorkflow : public QObject
         virtual void*           getOutput() = 0;
         virtual void            initVlcOutput() = 0;
         void                    initialize( bool preloading = false );
+
         /**
          *  Return true ONLY if the state is equal to Ready.
          *  If the state is Rendering, EndReached or anything else, this will