Solution for: Differentiate Locked and Unlocked Backgrounds (#4261)

1. Added two new background-specific styles to `customizer.styl` (4px gray border and 4px white border) and utilized them in `profile.jade` by checking for ownership of the asset and displaying a border (or not, as appropriate). 

2. Editor automatically cleaned up some trailing spaces on a few lines of `profile.jade`
Here's what I'd do:
```
ng-class="user.purchased.background.#{k} ? 'background-unlocked' : 'background-locked'"
```