monoids given by generators and relations...

clean up
Add makefile target for describing the state of prerequisites

    make describe
    ======= ../../DanGrayson-coq
    + git remote -vv
    origin	git@github.com:DanGrayson/coq (fetch)
    origin	git@github.com:DanGrayson/coq (push)
    sozeau	git@github.com:mattam82/coq.git (fetch)
    sozeau	git@github.com:mattam82/coq.git (push)
    upstream	git@github.com:coq/coq (fetch)
    upstream	git@github.com:coq/coq (push)
    + git describe --dirty --long --always --abbrev=40 --all
    heads/trunk-patched-0-g4e169b98f6de03c15ab6a080bffc9111f9cddf42
    ======= ../../Foundations2
    + git remote -vv
    origin	git@github.com:DanGrayson/Foundations2.git (fetch)
    origin	git@github.com:DanGrayson/Foundations2.git (push)
    upstream	git@github.com:vladimirias/Foundations.git (fetch)
    upstream	git@github.com:vladimirias/Foundations.git (push)
    + git describe --dirty --long --always --abbrev=40 --all
    heads/for-coq-8.4-0-g9f628a42f8af45f6e0021e7e648685e95f0b074a
    ======= ../../RezkCompletion
    + git remote -vv
    origin	git@github.com:DanGrayson/rezk_completion.git (fetch)
    origin	git@github.com:DanGrayson/rezk_completion.git (push)
    upstream	git@github.com:benediktahrens/rezk_completion (fetch)
    upstream	git@github.com:benediktahrens/rezk_completion (push)
    + git describe --dirty --long --always --abbrev=40 --all
    heads/master-0-g0513ee7ad6e98e1a53d375da7ce4b2a1b56b9b8a