testing improvements

Changes

#60 Update config.yml
#61 optimize ci
#62 More tests and fixes
#63 add coveralls badge to readme
#64 improve test coverage and fixes
#65 more tests for sio
#66 add styles for code snippets
#67 fix coveralls-public/issues/971
#68 Update eslint-plugin-node to the latest version 🚀
#69 update deps and improve sample login
#70 add node10 for ci tests and increase version number