Changes in version 0.2.0                        

  - This is a new version of the package.
  - Added new function op_summarise() for producing summary statistics
    of the time-series data.
  - Added new function op_compute_motionenergy() to produce motion
    energy i.e. frame-differencing.
  - Added new function op_compute_coherence() utilises the motion energt
    data to produce coherence measure.
  - Bug fix in op_plot_openpose, previous versions lines = TRUE did not
    work.
  - Improved performance of op_create_csv, it now utilises either the
    OpenPose tracking or derives participants by static seating
    position.