(bug 39431) Fix how SVG metadata is displayed (esp. animated status)

(bug 39431) Fix how SVG metadata is displayed (esp. animated status)

(Quite a few of these issues are my fault from 65c27ddeb19757cb8a)
*All fields were starting as collapsed, which was not the intent of the code
*Animated field used non-existent messages, and displayed a value of "1" instead
   of something meaningful to the user. Both (A)PNG and GIF handlers put
   the animated status in the long description which feels more natural to me
   so move the animated status to the long desc (long desc = subtitle under
   the image on the description page).
*Use human readable file sizes in the long description instead of
   total number of bytes. This bring it in line with the implementation
   in the parent class.
*Correctly mark scripted SVG's as animated. Mostly a moot point
   since we do not allow animated svgs past the upload checks
   but for completeness and for people who totally
   disable all upload verification.
   (Note: This would miss event attributes (onclick, etc)
   I didn't see much point in adding that since almost
   always there will be a script tag)

Patchset 3: trailing whitespace (d'oh)
patchset 4: rebasing so jenkins is happy

Change-Id: Ic58efbf2bf1e4b14e3129e5bce9ea920d9804111