remove checks and abouts
update gitignore
Merge pull request #2 from benediktahrens/removeprints

remove checks and abouts
add clean2 target to Makefile
Merge branch 'master' of github.com:UnivalentMathematics/Foundations
Merge pull request #3 from benediktahrens/gitignore

update gitignore
update README
Merge branch 'master' of github.com:UnivalentMathematics/Foundations