Fixes spacing in various places throughout the app

The spacing problem is compounded by the fact that there are multiple widgets adding padding to content: `nx-settings-panel` and `nx-info` chief among these. I’ve tried to true these up, giving each the same amount of padding (12px).

Where bare content exists, I’ve wrapped it inside a `nx-settings-panel`, so it doesn’t sit flat against the top/left of its parent container.

**Caveat:** There are instances where a `nx-info` block is nested inside a `nx-settings-panel` (e.g. the first pair of screenshots below), which defeats the above, but this PR improves the current situation, without attempting to rearchitect the way content is laid out.

Before:
![screen shot 2014-11-26 at 6 15 02 pm](https://cloud.githubusercontent.com/assets/186715/5211523/4aab3346-7599-11e4-94b6-6d0b164e381a.png)

After:
![screen shot 2014-11-26 at 6 15 33 pm](https://cloud.githubusercontent.com/assets/186715/5211524/4e20b5c8-7599-11e4-81be-6b51bc11cddf.png)

Before:
![screen shot 2014-11-26 at 6 15 56 pm](https://cloud.githubusercontent.com/assets/186715/5211525/516cc924-7599-11e4-8791-068bed9fe3d2.png)

After:
![screen shot 2014-11-26 at 6 16 09 pm](https://cloud.githubusercontent.com/assets/186715/5211526/5468f6ac-7599-11e4-853a-927e7323a01c.png)

Before:
![screen shot 2014-11-26 at 6 17 32 pm](https://cloud.githubusercontent.com/assets/186715/5211528/578ba2bc-7599-11e4-8336-744ce2eb226f.png)

After:
![screen shot 2014-11-26 at 6 18 39 pm](https://cloud.githubusercontent.com/assets/186715/5211530/5c3029dc-7599-11e4-833a-cccfa8a8da32.png)