Add easy_tst organize command

[brobsc]

• Add easy_organizer
  • Moves misplaced tst directories. Closes #35
• Add easy_tst arguments parser
  • Add watch command (default)
  • Add organizer command
  • Add -f flag to force organizer execution
  • Add -v for version
  • Add -h for help
• Refactor easy_helper and tst_wrapper
  • tst_wrapper
  • Add EXERCISES_DIR constant
  • Add get_exercises()
  • Refactor checkout()
  • Remove update_checkout (Moved to easy_helper as a general directory rename)
  • Use os.path.join instead of hardcoded paths
  • Improve cache flow
  • easy_helper
  • Add exercise_path()
  • Change rename_directory() to a generic function
    • Use shutil.move() instead of os.rename()
    • Fixes empty directories
  • easy_watcher
  • return on watch mode close, instead of pass