Show mana symbol cost when in column mode.

Hi Aeosynth,

I've never written any Javascript code, but I like your project and figured that adding a few easy features would be a good way to learn Javascript and React.  

Here's a patch that adds mana casting cost icons when in the column view.  I couldn't decide if I liked the icons before or after the name of the card, but settled on before since the name can get a bit long and cut-off the mana icons the other way around.

-Marcus