#609 Add fixed-point computations order option to CIF data-based synthesis tool

• The computations must now be able to be performed in any order. This leads to subtle changes in the code to detect a fixed-point. Since each of the three fixed-point computations has very similar code, I decided to merge them. Since this essentially leads to a rewrite of the entire fixed-point computations loops, I went with an incremental change approach. I moved the code from the three separate pieces of code to a common piece of code, part by part, in different commits. This merge request is therefore best reviewed per commit. However, a few changes are reverted or changed again in subsequent commits, as it was not possible to rebase them into older commits due to conflicts. Still, I hope the stack of commits is rather readable.
• I also improved the detection of the overall fixed-point over the different fixed-point computations, making it simpler.
• And I improved the data-based synthesis documentation a bit, here and there, mostly for linking to the performance documentation and to account for some earlier recent changes we made to the synthesis tool.

Closes #609 (closed)