fix(basic/type.ml): merge changes from simple-bmc, remove duplicate
types
fix: remove duplicate file, extract parsing module

1. remove duplicate file
2. extract parsing code into a module
fix: update _oasis file
feat(checker.ml): add basic checks and expansion

1. check flow var declared
2. check time variable
3. expand identity formula
feat(infix_parser.mly): integrate error checking into parser