added ehow.com

Added ehow.com downloader. 

def test_ehow(self):
        test_urls([
            "http://www.ehow.com/video_12303792_geek-vs-geek-debating-chromebook-3d-printers.html",
            "http://www.ehow.com/video_12255760_can-lose-muscle-dont-work-out-month.html",
            "http://www.ehow.com/video_12245067_cover-nail-holes-wood-floors-refinishing.html",
            "http://www.ehow.com/video_12252250_plant-avocado-seeds-water.html",
            "http://www.ehow.com/video_12238033_doityourself-metallic-tile-backsplash-ideas.html",
            "http://www.ehow.com/video_4755179_make-music-video.html",
            "http://www.ehow.com/video_4755198_history-movie-sound.html",
            "http://www.ehow.com/video_4755194_how-much-money-does-average.html",
            "http://www.ehow.com/video_4755182_write-comedy-act-script.html"

            ])