Christine

Mainly doing code refactor.
Add a `doer` class trying to make a simple rundown.
To achieve this, a `tools` package has been created to improve middle processes.

- `tools` now have
  - [x] emailer
  - [x] timer
  - [x] slider
  - [x] logger
  - [x] path_maker

- `doer` have
 - `run_down` procedure