Moved piles to the top, fixed width of piles (broke the line on mobile before), renamed "Hit me" to "Next round", added "New game" button.
helpers.cljs: fixed - is-touch-device gets called as a function in components/card.cljs - fixes JS error on hovering (cf. commit message of 0f24360f5605d0df91b3d9d1d846d643722c16ad)
.gitignore: added .DS_Store and .swp
README: added production build instructions.
helpers.cljs: unmark all cards when clicking on a marked card that's not discardable [fixes #28]
helpers.cljs: renamed discard-card to discard-or-unmark-card
Styling.