sparkles: fail travis build if test codes violate flake8/pep8 coding style check
cd test
-nosetests --with-coverage --cover-package pyecharts --cover-package test && cd .. && flake8 --exclude test,docs --builtins=unicode,xrange,long
+nosetests --with-coverage --cover-package pyecharts --cover-package test && cd .. && flake8 --exclude docs --builtins=unicode,xrange,long
