Add solver theory to README, remove spec#3

TheKnarf merged 1 commit intomaintheknarf-experiments/modular-svg:mainfrom

codex/summarize-solver-theory-in-readme.md-and-delete-spec.htmltheknarf-experiments/modular-svg:codex/summarize-solver-theory-in-readme.md-and-delete-spec.htmlCopy head branch name to clipboard