Added new methods (features)

Added 6 new very useful methods.
1. getScreenXDpi() which returns the Width (X) density in DPI.
2. getScreenYDpi() which returns the Height (Y) density in DPI.
3. calculateDistanceByX() which returns the distance between the given View's X (start point of View's width) and the screen width.
4. calculateDistanceByY() which returns the distance between the given View's Y (start point of View's height) and the screen height.
5. getViewX() which returns the X coordinate of the given View on the screen.
6. getViewY() which returns the Y coordinate of the given View on the screen.