National Geographic: In the past year, the U.S. auto industry has reeled under market pressure, faced bankruptcy, accepted billions of dollars in government bailout money, and agreed to mandates for cleaner and more efficient vehicles. But for two brothers from Colorado with an automotive start-up company, things couldn’t be better. Levi Tillemann-Dick, 28, and his brother Corban, 24, are carrying on a dream they hatched with their late father, Denver inventor and businessman Timber Dick, to bring to …