viewrendered.py plugin now works with default (rst) text.
- Revised docstring to accord with present command names.
- Removed very bad code introduced at rev 62984f9.  I'll omit the committer's name (not me) to spare his blushes.
- The s argument must be the *full* text, that is, p.b.  Don't put special-case hacks in general methods!
- In this case, the hack belongs in update_image.  I put the hack there, and update_image also works.

Leo build: 20140924100720