Magyar-sort

Header-only library for my take on radix sorting in-place.

Had this idea yesterday after watching "Creed"s video on youtube first on cache locality and stuff and then just normal radix sort (that I already know) in a recreational way.

It struck me when watching the videos in this order that his counting sort variant of course needs a separate array. He even says it would be good if could be done in place... I was like... but hey! I can do it in place!

Biggest relevation was realizing that prefix sums will already tell me from-to areas of sets in coded that were already sorted by its first (radix-loop choosen) digit. I just need to keep the prefix sum around in an untouched copy.

Maybe better to do it on nibbles for better cache usage and do all "digits" at once in a single big loop. Then algorithm is recursive: first do biggest digit, then prefix sum1-2 will tell where digits "areas" start and end. Between them we either recurse and do a small radix on second char OR if the thing is small enough just do regular sort on it and that is all...

Also might be helpful to know starting digits are unused - small num support?

Will need to code it, has it on paper. Should be fast and cache-friendly!