Some great news on the Selena Gomez front. A source close to the Disney superstar tells E! News the pop princess was "in and out" of a Los Angeles-area hospital over the weekend for tests and checkups, but is doing much better since falling ill and seeking emergency medical attention after last Thursday's Tonight Show appearance. "She spent the weekend resting and feels stronger," the insider tells us. "No more nausea or dizziness." The 18-year-old Gomez apparently suffered from a nasty combination of exhaustion and food poisoning, and her condition was worrisome enough that boyfriend Justin Bieber  skipped Friday night's Stanley Cup Finals featuring his hometown team,...