Revert "Add factor-regex and mathop-regex"

This reverts commit 090d0850cb977e802a9a9dc21cac8ec1959c86fa.
Revert "Remove everything for now"

This reverts commit 0ed25406163872fd6bd3656517727f112a342505.
Revert "Move the EBNF"

This reverts commit e53b1262a45e1851e22c5f91636b92b2217fddab.
Revert "Add a simple LISP math grammar in EBNF"

This reverts commit 6fbf6eafd44535c518310eeb23a54d95023685f8.