Documentation rendering issues on IE and Safari

[purdrew]

Noticed some rendering issues on IE and Safari:

IE (10, 11, Edge):

• index.html - Navigation links (Docs, Repository) at top are not visible.
• index.html - Hero element does not reflow correctly on small screens.
• index.html - Column features are not honoring the max width.
• docs.html - Does not render at all

Safari:

• docs.html - Have to double click navigation elements in the left hand nav to get them to work. Single click just highlights the nav link.

[purdrew]

IE (10, 11, Edge):

*index.html - Navigation links (Docs, Repository) at top are not visible.
*index.html - Hero element does not reflow correctly on small screens.
*index.html - Column features are not honoring the max width.

The above are due to differences in IE flex box implementation.

*docs.html - Does not render at all

Lack of rendering is due to Polymer/vulcanize#223

Safari:

• docs.html - Have to double click navigation elements in the left hand nav to get them to work. Single click just highlights the nav link.

It appears that paper-item may be trapping the first click on Safari for some reason.