Don't reload the current game if selected.
Implemented Polymer core-drawer-panel.

For the sidebar and main content parts of the page. It has a really
swish animation for when the screen is small, the drawer disappears.
Tweaked card styling.

Values are from Polymer's designer.
Fixed JS bug.

Introduced when adding the core-drawer-panel.
More work on the Polymerised sidebar.

Tabs are now functional, styling of content is better. Also improved
styling of apply sorted load order button, and got rid of some obsolete
CSS.