Use automated testing to find Python syntax errors

[cclauss]

• https://travis-ci.org/salesforce
• https://travis-ci.org/salesforce/decaNLP # The repo switch would need to be turned on.

http://flake8.pycqa.org will flag the Travis CI build if there are Python syntax errors or 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. This PR therefore recommends a flake8 run of these tests on the entire codebase.

• 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

[bmccann]

Awesome! I wrote all of this in Python 3 without any respect for things that would break in Python 2, so those tests will break. Everything is setup to run inside a Docker container with Python3, so I'm going to remove those tests for now. 6662a33dae348e65e03bbb593919fff1055a836c

[salesforce-cla[bot]]

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