Load Data From External Text File

The goal: (1) While developing my game on my PC, load story info from a text file, located in /Assets/Resources or anywhere else it needs to be. (2) While demonstrating the game in Web player format, load the same info from a text file, located at (eg.) www.example.com/code/myproject/test.txt, the same directory as the Build.unity3d file. (Ideally in a subdirectory.)

What I've got so far:

 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 
 public class TextFileLoader : MonoBehaviour
 {
     public WWW www;
 
     // For showing/storing the result
     public string result;
     public Text output_text;
 
     IEnumerator Start()
     {
         Debug.Log("Data path: " + Application.dataPath);
         www = new WWW( Application.dataPath + "/demo.txt" );
         Debug.Log(www.url);
         yield return www;
         result = www.text;
         Debug.Log("Result: " + result);
         output_text.text = result;
     }
 }

I run this locally on my computer, with the text file in both the main Assets directory and in Assets/Resources. Result: debug statements say "C:/Users/Kris/Documents/Unity/WizardGame/Assets", and "C:/Users/Kris/Documents/Unity/WizardGame/Assets/demo.txt". In other words, the variable "www.text" is being set to the full path of my file, not its contents. Which is odd because if I pause Unity, variable "result" is blank even though I explicitly set it and the debug statement says it's not blank! If I build my project and run, it actually works now, but it doesn't work while I'm just hitting the Play button within the editor. That's bad because it greatly lengthens the build-and-test cycle.

How can I make this code work in the editor, without having to build each time I want to test? My fallback plan will be to use Resources.Load and then change the code at the last minute before uploading my project, but that's bad practice.

(Unity 4.6.)