Allow users to specify symbols for a given plot

[brittsikora]

Allow users to specify a symbol (other than circle) for a given plot

Example Brian A sent to Jeremy:

Test notes

• The event_symbols setting controls what marks appear in the chart, which include circles (default), squares, diamonds, and triangles (multi-directional). This settings object shows a few of them off:

  {
  event_symbols: [
      {
          events: ['Enrollment'],
          symbol: 'triangle',
          direction: 'right'
      },
      {
          events: ['Randomization'],
          symbol: 'diamond'
      },
      {
          events: ['Study Completion'],
          symbol: 'triangle',
          direction: 'left'
      },
      {
          events: ['Adverse Events', 'Concomitant Medications'],
          symbol: 'square'
      }
  ]
  }