make titlebar component responsive

[jameshadfield]

(after #121)

[trvrb]

@jameshadfield ---

I tried to do this in #189, but ran into an issue with making putting browserDimensions into redux in index.js instead of app.js (one level up). I got the redux boilerplate working, but couldn't figure out how to get dispatch going.

I thought it would be easiest to make titlebar responsive by making browserDimensions available everywhere and then just querying browserDimensions.width to see whether to draw the "nextstrain" logotype or to draw the circular logo.

If this sounds reasonable to you, would you mind taking a look at getting browserDimensions working throughout static content?

[jameshadfield]

No problem - this is done in branch browser-dimensions

If it looks good then you can merge into your working branch I think

[trvrb]

Awesome. This is super clean. Thanks James.

[jameshadfield]

Browser dimensions bug now fixed in master - 3af9398