Update ViewController.m
Update ViewController.m

Added a code to demonstrate a FGThrowSlider with image files.
Update FGThrowSlider.h

New instance and class method for creating a FGThrowSlider using UIImages
Update FGThrowSlider.m

Method for creating FGThrowSlider using UIImages
Update README.md

Included new method
Update README.md
Merge pull request #1 from lewisgodowski/master

Added functionality