Photo: 9to5Mac.com Apple’s Senior VP of Software Engineering, Craig Federighi, has officially debunked the longstanding myth that users should quit background iOS apps in order to improve performance or save battery life, 9to5Mac reports. A 9to5Mac reader emailed Apple CEO Tim Cook asking the company for an official stance on whether this was necessary. The message was passed on to Federighi who responded with an uncategorical “no.”…