Fix deadlock in ViewLayer.draw methods, #11

Resolved merge conflicts.

The commit changes the order of acquiring locks in both of the ViewLayer draw
methods to first lock the OpenGL context before locking uninitLock.

iina/ViewLayer.swift

@@ -164,7 +164,6 @@ class ViewLayer: CAOpenGLLayer {
           ]
           mpv_render_context_render(renderContext, &params);
         }
-        videoView.player.mpv?.unlockOpenGLContext()
       }
       needsMPVRender = false
     }