Digital distribution keeps gaining momentum. While there are currently about 2,600 movies available for download on iTunes, including a number of independent movies and documentaries, that number will soon grow. New Video Digital confirmed this week that it has secured a whopping 1,600 titles for Apple‘s online store and other outlets. The independent video aggregator said that it has acquired the rights to over 5,000 hours of independent film and television content, with plans to double that number by the end of this year. The company will push that content out …