First round of design tweaks to the Gallery view.

- If the aspect ratio of the image is *almost* the same as the window
  aspect ratio, then scale the image to fit, so that the user doesn't see
  thin black bars. (the user may still zoom out to see the full image)
- Now trimming whitespace from descriptions.
- Using dash instead of colon for Author and License.
- Adjusted color of Author and License.
- Decreased the resolution of fetched images :( since very high-res images
  may use a prohibitive amount of VM memory, and will not render correctly
  on some devices.

Change-Id: I88df4782576775486f67838a180b7fb9e9e78bd2