Apple has filed its annual 10-K report with the SEC, revealing another jump in research and development expenses, among other details. The company spent $4.48 billion on R&D in 2013, a 32 percent increase from last year’s $3.38 billion expenditure. Apple also now has 80,300 full-time employees — last year, the number was 72,800. The report also notes that the company plans on opening “about 30 new retail stores” in 2014, with…