`<Main>` doesn't really belong in App.js given the html it renders,
but there's some additional thing happening with this component
that requires it to be here to support tests. This update addresses
the extra padding that it creates by being used at this level.
Closes#17
The Main component in the LandingPage component has been moved to the
App component. This is required so the tests can mock the store without
any insights information.
