Make header_left an id, not a class.

I think this was a mistake, it seems to be an id in the other places it
is used.
Add a div around the main content.

Makes it easier to style.
Remove extra whitespace.
Use alternative footer template in responsive layout
Add wrapper div to make styling easier.
Put the 'no results' text in a result_section div

Makes consistent styling easier.
Slightly wider modal dialog

In order to display wider layout of sign in options.
Remove foundation dropdown

Currently unused.
Style new game div

Make it cover 8 cols of 12.
Center sidebar text on wider screens.
Nest grid rows to keep outside edges aligned.
Add grid-row elements to contain the grid-columns here.
Make #sign_together and #sign_alone grid rows
WIP