Rename Button.rawDisplay to display
Merge pull request #15 from NetLogo/wip-rename-rawDisplay-to-display

Button's `rawDisplay` should be `display`
Adding tests for things that were failing in Tortoise
Seal InputBoxType
Limit Chooseable options to string, double, boolean, logolist
Textbox escapes and unescapes display string on parsing and writing
Allows chooser to have a default value of a string containing "//"
Represent widget constraints as data objects
Move ConstraintSpecification trait out of Widget.scala