(Reuters) - Visa Inc missed analysts' estimates for revenue and posted a 14% rise in operating expenses for the first quarter on Thursday, sending its shares down nearly 2%.The world's largest payments network has been spending more on rewards and incentives such as airport lounge access, roadside assistance programs and travel insurance, which pushed up operating expenses to $2.04 billion (1.6 billion pounds) in the three months ended Dec. 31.Payments processors have also leaned on..