[Refactor] Refactors all Less files from the docs site into Javascript

[mmrtnz]

• Creates StyleResizable mixin
  • Watches when the window is resized and updates the accordingly.
  • Because it is a mixin, components that utilize StylePropable have been reverted to ES5 syntax.
• Minor style changes to the following component
  • EnhancedSwitch
    • labelWidth is now calculated using css' calc attribute rather than accessing the DOM element.
    • Simplied styles between label and switch elements
  • DropDownMenu
    • width is not set by the component if it is defined in this.props.style
• Removes gulp related less files