refactor(library): rename exists_elim and exists_intro to exists.elim
and exists.intro
refactor(library): rename theorems "iff.flip_sign -> not_iff_not_of_iff" and "decidable_iff_equiv -> decidable_of_decidable_of_iff"
feat(init): reserve notation for "not in"
fix(library/normalize): bug in the "eval" command
refactor(library): add compile_equations function, generic_exception, and cleanup elaborator_exception
test(tests/lean/extra): more tests for equations compiler
chore(hott) try to move library
chore(hott) delete old hott lib
chore(hott) fix file endings
chore(hott) fix init
chore(hott) add function.hlean to init
chore(hott) fix the types and algebra
chore(hott) reflect @avigad's name changes in the std library
chore(hott) minor corrections
fix(tests/lean): adjust tests to recent changes in the lean libraries
refactor(library/data/int/basic): make the integers an instance of ring