Card filtration controls

[onecrayon]

It needs to be possible to control which cards are being shown in decks listings. This requires a new auto-completing input element, but I'm going to roll it out in two phases:

• Implement basic display element to allow removing card filters from the listing #112
• Implement full auto-complete input element for adding and removing cards from the listing

Note that the current basic card filtration also doesn't kick in when navigating through browser history (probably because it's not being watched).