Linked Files - Open Read-Only

```
Use the read-only feature added in issue 210 to open linked files in read-only 
mode.  This way, the integrity of the linked file is maintained, as is the 
concept of using the linked file in SimpleIDE.
```

Original issue reported on code.google.com by `jmar...@parallax.com` on 13 Oct 2013 at 8:04
