Realtor.com unveiled a rental app today that enables users to search for rental properties on iOS and Android smartphones. The app aims to bring realtor.com, which is operated by Move Inc., up to speed with competitors Trulia and Zillow. Zillow launched a rental app for Android in April 2012, and a version for iPhone later that year in September. Trulia released an Android rental app in 2011, and added an iPhone version in April 2012. The app features an image-focused interface, allowing users to scroll through listing photos from a search feed. And it allows apartment, condo and house hunters to filter by specifications like parking, in-unit laundry and pet policies. It also allows people to filter by listings they have viewed and contacted, as well as receive alerts when properties...