Draws horizontal timeline in the current axes. The name of each track appears as a label on the y-axis. Each element of the starts and ends cell arrays is itself an array, so each track can start and stop either once or many times.
Credit: Kevin Bartlett (firstname.lastname@example.org), 2012
tracks (cell): An array of timeline track names.
starts (cell): An array of vectors that indicate segment starts.
ends (cell): An array of vectors that indicate segment ends.
varargin[LineSpacing] (double): A number between 0 and 1, places
adjacent timelines the specified fraction of the line widths apart.