Proposal: `.render()`

[asg017]

• render(cell, type, options)
  • cell - name of the cell to render.
  • type - one of text, html, svg, png, jpeg, jpg
  • options - object with config for whichever method is picked

1. Simplicity, pass in args from CLI, documentation would be cleaner, examples easier to follow
2. Can do optimizations under the hood (e.g. canvas toDataURL instead of screenshot