Code cleanup, buffering, transition from edges instead of corners, smaller changes

- Code has been cleaned up (indentation, missing semicolons added, insecure operations replaced)
- Buffering for images has been added (defaults to 5): will only pre-load a certain amount of images, so that not all images load at once
- Transition will now animate from edge to edge of an image, not from corner to corner. Images with a ratio < than the wrapper ratio will move from top to bottom (or reverse), other images from right to left (or reverse).
- "onEnd" function added for restarting the slideshow.
- IE 8 fix for maxSlides calculation added
- Fixed calculation of image size - images will never be smaller than the wrapper anymore
- Changed default 3d transition to "linear"