Changes in version 0.4                         

  - Many minor improvements.
  - Unified functions and arguments, changed function naming scheme from
    lexis.grid() to lexis_grid().
  - Set legacy functions to .Deprecated.
  - New feature: lexis_lifeline() now lets start and end lifelines at
    arbitrary points in time.
  - New feature: lexis_polygon() can draw arbitrary polygons inside a
    Lexis grid.
  - Improved support for HMD Lexis Triangle data.