MOVE: src directory to perid directory
ADD: Perid Language Example
FIX: emacs temporary file ignore
ADD: perid main package
ADD: MILESTONE
FIX: MILESTONE and TODO update
FIX: use operator in sample code
ADD: Miner: Operator token
REFACTOR: Miner: Test
FIX: Miner: Regal Paser
FIX: Generator
ADD: Casting: Operator Yacc
FIX: ignore: emacs temporary file