v0.3.1

• Breaking change: scribble now only accepts hexadecimal pen colors. You
  can still use rgb() syntax by calling the rgb() function in R: instead of
  "rgb(61, 255, 232)", you can write rgb(61, 255, 232, maxColorValue = 255).
• Fix a few other minor issues with scribble:
  • Fix toolbox unminimizing after mouseover when it should stay minimized
  • Don't show the eraser cursor until the mouse moves