* Travis CI: Add flake8 to the testing 

Add [flake8](http://flake8.pycqa.org) tests to find Python syntax errors and undefined names.

__E901,E999,F821,F822,F823__ are the "_showstopper_" flake8 issues that can halt the runtime with a SyntaxError, NameError, etc. Most other flake8 issues are merely "style violations" -- useful for readability but they do not effect runtime safety.
* F821: undefined name `name`
* F822: undefined name `name` in `__all__`
* F823: local variable name referenced before assignment
* E901: SyntaxError or IndentationError
* E999: SyntaxError -- failed to compile a file into an Abstract Syntax Tree

* learn-python should not teach the antipattern of bare exceptions

See PEP8 and https://realpython.com/the-most-diabolical-python-antipattern

* noqa F821 - We are intentionally raising NameError

* Two consecutive blank lines before a function definition

* flake8 --max-complexity=10 --> 12

* pylint: disable=broad-except

* Update test_tuples.py

* Update test_tuples.py

Fixed code style issues. (Trailing whitespace, blank line whitespace and line length too long)

* Update test_tuples.py

* Update test_tuples.py

* Update test_tuples.py

* Update test_tuples.py

* pep8 compliant

changed "you're" to "you"

* Added simple descriptions to files missing descriptions at the top of the files.

Added simple descriptions/summary for test_class_objects.py, test_inheritance.py, test_method_objects.py, test_multiple_inheritance.py, test_file_methdos.py, test_file_reading.py, test_math.py

* removed trailing spaces

* main README.md updated

* Adds README.pt-BR.md

Co-authored-by: vilmacio22 <vilmacio22@users.noreply.github.com>