Various UI changes for nicer look

**Changes**
* Removed border from overlay. (See notes below)
* White caption background
* Info overlay (scaling %) now spaced equally from image on right and bottom sides

![screen shot 2013-10-27 at 4 18 24 pm](https://f.cloud.github.com/assets/1301625/1416281/00297228-3f45-11e3-9f49-33370f9082b6.png)

**Rational for removal of border:**
* There was no apparent documentation to the end user what the blue border meant. Only after digging in the code did I learn that it indicated the link was to a page and not an image.
* Looking at the link location at the bottom of the window in the status bar would indicate to the user what type of link it is. Having a border colour duplicates this information.
* Subjectively, I thought the overlay looked better without a border.

If you're still keen on displaying to the user what kind of documents the images link to, let's discuss a better way of doing it. Preferably a method that would be obvious to users right from the start. Otherwise, I'll clean up the code to remove all traces of the border code.

Tell me what you think about these changes.