Revert "extract token tokenizer and evaluator"

This reverts commit 6671f09baaed23adaefd043058b400f191aa9641.
Revert "specify tokenize and evaluate methods"

This reverts commit 631acb6dabc88a86959cc0af785a5b5b5b9eff94.
init questions and tasks
able to eval one number
able to eval plus two numbers
able to eval one operation of two numbers
refactor reduce switch case use call method by symbol
able to eval multiple operation of three or more numbers without priority
extract methods of tokenize and evaluate
Merge pull request #1 from Zhengquan/master

Two stacks evaluator and naive tokenizer Without Priority