Add a night mode display

*implemented on 8Aug2013*

Maybe.

Like ToledoTalk.com/parula code, allow for different CSS themes to be used via a cookie.

For JotHut/junco, provide two theme options: the current or default view and the white on black view (or is it light gray on charcoal). Like Toledo Talk's Jan18 theme.

*22jul2013* - will require significant CSS changes, so I'll wait until the main CSS file is stabilized.

#resolved
#junco