Define Output concept

FaceOutput and FacePosition concepts definition:

• Step 1 - create the concepts

$ ofc new concept face_output,face_position --dest=DIR:./face-app

• Step 2 - add new properties

$ ofc new property face_position name:string,x:integer,y:integer,width:integer,height:integer --dest=DIR:./face-app
$ ofc new property face_output faces:face_position:1/n --dest=DIR:./face-app