add flake8 to travis testing

[AYZhu]

This ensures that we test for pep8 compliance during Travis instead of self-enforcing.

[coveralls]

Coverage remained the same at 100.0% when pulling fd1479c on AZtheAsian:master into 71ff3b7 on ninuxorg:master.

[nemesifier]

@AZtheAsian welcome! Thanks for taking this, you are almost there, please read my inline comment.

[nemesifier]

This needs improvement, please proceed as follows:

1. set the line length to 110 characters in a similar fashion this example setup.cfg file (it means adding a flake8 section and a max-line-length = 110 line
2. remove the --ignore flag entirely
3. fix any issue that comes up

[rohithasrk]

@AZtheAsian Also squash all the commits into and change the commit message to something like [QA] Added flake8 check to Travis tests. QA means Quality Assurance and also notice that we've used past tense in the commit messages. Good job btw!

[coveralls]

Coverage remained the same at 100.0% when pulling 0861e2e on AZtheAsian:master into 71ff3b7 on ninuxorg:master.

[coveralls]

Coverage remained the same at 100.0% when pulling 48cfbba on AZtheAsian:master into 71ff3b7 on ninuxorg:master.

[auvipy]

you need a newline at line number 5

[nemesifier]

@AZtheAsian sorry for the wait, @auvipy is right regarding the new line comment, please pay attention to comments from other mentors too next time, for this time I'll take care of adding the newline.