safari fix when including SVG on front page

Apparently, the SVG standard actually says that when an SVG element doesn't
specify a size, it should take up the entire available space in its parent.
Safari seems to interpret that by implicitly setting the height to 100%,
(the width is explicitly constrained by the bootstrap properties). This
takes up too much vertical space.

I'm trying to just explicitly set a parent div to 200px. thinking that
will be larger than the width of a (sub) col-md-4 for even very large screens
and won't affect the other browsers (tested firefox and chrome) too much.
Update the style for the navbar

The .selected class is set based on the most recent URL change in the
NavCtrl.
Merge pull request #60 from paulfred/master

Styling up more pages