Added section of known issues to README.md
Added section of known issues to README.md

manifoldjs/ManifoldJS,BobJavascript/ManifoldJS,f2bo/ManifoldJS,ArchivedRepos/ManifoldJS,f2bo/ManifoldJS,dragthor/ManifoldJS,NoobsArePeople2/ManifoldJS,f2bo/ManifoldJS-lib,f2bo/ManifoldJS-lib,maitret/ManifoldJS,AuyaJackie/ManifoldJS,beni55/ManifoldJS