v0.3.17

• Premailex.HTMLInlineStyles.process/3 now warns when styles can't be loaded from URL's #74
• Premailex.HTMLInlineStyles.process/1 now parses <thead> and <tfoot> elements #75
• Premailex.CSSParser.parse/1 now handles escaped commas #77
• Require Elixir 1.11 #74