run on all MTG Salvation elements, not just #posts

This change causes Scry to work on the MTG Salvation wiki (and the articles), not just the forum.

BTW I'm getting this error when I run the extension in Chrome:
```
Denying load of chrome-extension://ohbcmjjmlnledindjhlljfijfmbncahj/lib/jquery-2.0.3.min.map. Resources must be listed in the web_accessible_resources manifest key in order to be loaded by pages outside the extension. 
```
but it seems to be harmless.