auto-complete in nodeBody textArea editor

[radiatoryang]

• will probably rely a lot on this for info / implementation: http://www.clonefactor.com/wordpress/public/1769/
• we're not using TextField, we're using TextArea... so instead have to use TextEditor.SelectWord to grab the current word being typed, and then compare word distances there
• user can define a custom list of auto-complete terms too, good for keeping speaker names consistent?
  • or automatically detect speakers? hmm
• wish list: use reflection to automatically detect all YarnCommands in code base? is that possible?