Update icon docs. Fix missing example. Improve doc on importing icon sets.
Group imports & add comments.
Fix paper-tabs documentation in tutorial
Merge pull request #526 from arthurevans/icon_updates

Update icon docs.
Fixed code highlighting.
Merge pull request #531 from arthurevans/docs-500

Fixed code highlighting.
Merge pull request #522 from menelaos/tutorial-step1-fix

Fix paper-tabs documentation in tutorial
Code styling fixes:

-   For all <pre> blocks, allow horizontal scrolling
    instead of wrapping text.
-   For side-by-side element in tutorial, keep code
    block from stretching vertically.
-   Use link color for <a><code>. Nesting <code><a>
    already works, but is error-prone; this just ensures
    we use the right color either way.
Removed commented-out property.
Merge pull request #532 from arthurevans/tutorial-codeformat

Code styling fixes