“Good evening. Hello. I have cancer. How are you?” That’s how comedian Tig Notaro started her set at Largo on August 3, 2012. She’d had a rough year: pneumonia, the death of her mother, a breakup and, finally, a breast-cancer diagnosis. But those terrible experiences led to a professional whirlwind that included a best-selling, Grammy-nominated album. We caught up with Notaro as she set out on her latest comedy tour.