Jawbone has released Era ($130), a new Bluetooth headset. Era is being billed as “the smallest, lightest, most comfortable” headset made by Jawbone. Its NoiseAssassin technology eliminates background noise. Era offers up to four hours of talk time, which can be doubled with use of its charging case. An app displays battery life and lets users program the Talk button to access Siri directly from the headset. The headset comes in four different…