Good news for those of you who are averse to agonizing plane trips and high ticket prices: hot travel search startup Hipmunk has just launched a new feature that makes it easier to cut back on both. The new feature, which is called FlexCal flight search, is designed for users who have flexible travel dates. Give the site a ballpark range of when you want to depart, and it will present visual bar graphs charting which days have the lowest fares. Of course, other travel sites have had similar features for some time, so this isn’t really unique to Hipmunk. But Hipmunk’s interface is significantly less headache-inducing than many of its competitors — and it includes its trademark ‘sort by agony’ feature, which lets you rule out any flights that would be particularly painful (say, that red-eye with two stops). Other recent Hipmunk developments: the site, which is coming up on its first birthday, now includes a Wifi icon next to any flights to offer in-flight Internet connectivity. And...