Just a few short years ago, if you wanted to produce a new gadget or raise money to make an independent film, you had no choice but to scrape together funding on your own ... or hope a generous friend or relative might put up seed capital. These days, there's a new approach: crowdfunding. Sites such as Kickstarter, Indiegogo, and GoFundMe can not only help you raise money to fund your idea or cause, they can also help you establish a community of...