Add wrap algorithms to stop code repetition

There are several codes, such as OS-SART, SIRT, SART, or AwPCSD, OS-AwPCSD (etc) that are essentially the same algorithm but with a block-based update or a per-projection update. In theory, we could just have a single algorithm, e.g. OS-AwPCSD, and then AwPCSD would just be a wrapper to OS-AwPCSD, but with a fixed block size of 1.

This will make everything much tidyer .