Indent 관련 Issue 정리 및 개선 사항

[1] Indent 관련 Issue 발단 과정

• Found Problem Not Working, Question about Formatting
  Fix codes in more-python/chapter 1 #6
• Found Reason of the problem Not Working, Confusion with Spaces and Tabs
  Fix good.py #9
• New issue started about PEP 8’s 4 spaces Comment on PR #9
• Unified indents to tab Unify indents to tab #10
• New issue opened about Indentation Consistency Indentation Consistency Issue #11
• Decided to use 4 spaces indentation, New issue about diving roles, branches 4 Spaces Indentation issue #15
• Divided Branches and Roles, start on 4 spaces indentation works. Unifying indentation to 4 spaces indent #20

[2] Indentation to 4 spaces indent 진행 상황

Unifying indentation: python-for-beginners/chapter 2-4
Unifying indentation: python-for-beginners/chapter 5-7
Unifying indentation: python-for-beginners/chapter 8-10
Unifying indentation: python-for-beginners/chapter 11-13
Unifying indentation: python-for-beginners/chapter 14-16
Unifying indentation: python-for-beginners/chapter 17-18
Unifying indentation: more-python-for-beginners/chapter 1-3
Unifying indentation: more-python-for-beginners/chapter 4-6
Unifying indentation: more-python-for-beginners/chapter 7-9
Unifying indentation: even-more-python-for-beginners-… chapter 1-5
Unifying indentation: even-more-python-for-beginners/chapter 6-10 Unifying indentation: even-more-python-for-beginners-… chapter 11-15
Indent unify of python-for-beginners
Indent unify of more-python-for-beginners
Indent unify of even-more-python-for-beginners-data-tools