At the sold-out and uncomfortably crowded Colin Meloy concert last Friday night at Iota, you could hear whispers of discontent make their way through the audience. “I can’t even move!” or “This is ridiculous; they obviously oversold the show,” or “That jerk just spilled beer on my shoe,” and perhaps the most common lament: “Where’s Colin?!” But when Meloy, the front man for Portland indie folk group The Decemberists, took the stage grinning mischievously and launched into acoustic versions of his notoriously quirky songs, all restlessness and disgruntlement disappeared.