Add capability to decompress jpeg to yuv image.

Add capability to decompress jpeg to yuv image. #35

New flag for limiting progressive jpeg scans

Using libjpeg-turbo 2.1.0 or later is required to make TJFLAG_LIMITSCANS work.
https://github.com/libjpeg-turbo/libjpeg-turbo/releases/tag/2.1.0

PyTurboJPEG 1.4.2

getting possible scaling factors for direct rescaling from jpeg.scaling_factors

PyTurboJPEG 1.4.1

First release on the GitHub.