Update references to paper

During revision, I added Lemma 2.5 to the paper, changing the numbering.
This commits updates the numbering in the formalization.
Prove new lemma 2.5 from paper
Update Agda version in README.agda
Merge pull request #4 from inc-lc/topic/update-READMEs

Update READMEs and paper/formalization mapping, find slip in paper