Nit ~little~ improvements

[raphamorim]

• Remove use strict. Since we're using nodejs 10: strict modes are used by default.
• Add test script
  • It's nice and intuitive (plus: avoid dependency of husky to run all the tests. When I mean husky: I mean *.js file changes triggered by git hooks)
• Fix the broken tests by add gauchesco dialects from RS #58
• Add editorconfig rules for markdown
• Add trim_trailing_whitespace rule for JS files (friendly for vim/emacs without plugins and get better GH diffs)

[vercel]

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[mvfsillva]

Thanks my friend for helping me!