4.0.0

• Drop support for Node 0.12
• Update postcss-easy-import to 2.0.0
• Update fs-extra to 2.1.2
• Update autoprefixer to 6.7.7
• Update postcss-apply to 0.6.1
• Update postcss-color-function to 3.0.0
• Update postcss-reporter to 3.0.0
• Update postcss to 5.2.17
• Update stylelint-config-suitcss to 11.0.0
• Update stylelint to 7.10.1
• Update devDependencies to latest