ConvertClip: Add JavaDoc
Rename ConvertClipIterableRT to ConvertClipIterable

* Remove RealType restriction on generics
ConvertClipPixelRT: Add JavaDoc
ConvertCopy: Add JavaDoc
ConvertCopyIterableRT: Add JavaDoc
ConvertCopyPixelRT: Add JavaDoc
ConvertNormalizeScale: Add JavaDoc
ConvertScale: Add JavaDoc
ConvertScaleIterableRT: Add JavaDoc
ConvertNormalizeScaleIterableRT: Add JavaDoc
NormalizeImgRT: Add JavaDoc
Refactor ScalePixel interface

this implementation is easier to understand and even more flexible