[ALOY-290] Android Screen Density based resourses

At the @0.2.34 version we found the platform specific folders for views/styles/controllers and with the formFactor attribute we can develop thinking in specific platform (handheld or tablet). But the Android Platform has 4 groups of screen (LDPI, MDPI, HDPI and XHDPI) and it's a bit hard to build different views for different screen density. Like @tonylukasavage says, The purpouse of this Issue: be able to use alloy views/controllers/styles not only based on platform, but also in the case of android, based on screen density. Such as the image attached (Screen Shot 2012-09-21 at 8.47.27 AM.png). It will help us to build apps more flexible for each platform and screen density (in the case of Android). One example for this use: For LDPI Android screens, we can build screens more focused on the base application task only (in my case an app for soccer lovers) and split the features in other screens/actions, but with HDPI we can use the large height screen and shows more information about the team, players, use images with more details and bigger!