IDEA: task-oriented menu items

[ByronAhn]

add some menu items (to the TextGrid editor) that are oriented towards different points in the process of PoLaR labelling:

• menu item: "getting started"
  • view settings
  • ensure polar tiers exist
• menu item: "check this"
  • run levels
  • runs syntax checker
  • run SLA
• menu item: "finishing up"
  • runs levels
  • runs syntax checker
  • offers save dialog