Added second status line for War events.

Added a second status line under the first, to show which cards are placed down during a war event.
Also added some clearfix CSS from a Code Academy TA.
Moved CSS to separate stylesheet.

Created stylesheet.css, linked to .html.  Also fixed some formatting issues.
Moved javascript to separate file.

Moved the javascript into the warcards.js file, removing all inline JS.
Added clearWar function to clear War event text.

Added clearWar, which is called if the play button is pressed after a war round.  Also fixed some
formatting of the status text lines.
Reformatted HTML with HTML5 tags.

Changed div tags within warcards.html to appropriate semantic tags such as header, footer, and
section.
Updated README.