D-8

v-1.0
---
1. add listener: initial
    "Play", "Stop"

  	==> done
D-8

v-2.0
---
1. add listener => "Stop" ::complete

  	==> done
D-8

v-2.1
---
1. add listener => "Play"   ::complete

  	==> done
D-8

v-3.0
---
1. add listener => initial

  	==> done
D-8

v-3.1
---
1. SBL => onStopTrackingTouch

  	==> done
D-8

v-3.2
---
1. Play => use saved position

  	==> done
D-8

v-3.3
---
1. Introduce: Service_ShowProgress

  	==> done
D-8

v-3.4
---
1. Introduce: onCompletionListener

  	==> done