code: function diffText(a,b){
  	var changes = []
  	var text = a
  	while(text !== b){
  		var c = partiallyDiffText(text,b)
  		if(c.type === 'add'){
  			text = text.substr(0,c.index)+c.value+text.substr(c.index)
  		}else{
  			text = text.substr(0,c.index)+text.substr(c.index+c.many)
  		}
  		changes.push(c)
  	}
  	
  	return changes
  }
docs: produces one or two changes that succinctly describe the changes to the text