additional functions for the player SimpleSkip:
  - getPercentBufferHigh
  - getPercentBufferLow (moved from .cc to .h)
Player: logging variables and their getters for:
   - Time that the player starts
   - Sequence number of the first chunk to play
modified the function captureVideoBuffer() to set also the start, end and the head of the video buffer
added the getter getState for the DonetBase