* add unittest test=develop

* add function cache test=develop

As the title, we add decorator "dygraph_to_static_code", and add related "get_code", "get_func", "get_output" for ProgramTranslator. Next step will be adding "dygraph_to_static_program"

1. Rename AutoTracer to ProgramTranslator
2. Rename cached_program to program_cache
3. Remove some functor style __call__
4. Dict key should be string but not hash code of string

As the title

1. Add support for Break and Continue in Dygraph to Static
2. Also add support for gast.Not in NodeTestTransformer
3. Also add support for logical op transformation in LoopTransformer