v4.0.0 - remove IE8 & 9 support

• ✂️ Remove IE8 & 9 code
• ✂️ remove IE8 dependencies: fizzy-ui-utils, doc-ready, get-style-property
• ⬆️ outlayer v2.
  • replace EventEmitter with smaller ev-emitter
  • isOption changed to option. Maintain backwards compatibility with old isOption names:
    • isFitWidth -> fitWidth
    • isInitLayout -> initLayout
    • isLayoutInstant -> layoutInstant
    • isOriginLeft -> originLeft
    • isOriginTop -> originTop
    • isResizeBound -> resize
    • isResizingContainer -> resizeContainer
• ⬆️ jquery-bridget v2. Change jquery.bridget.js path to jquery-bridget.js
• ⬆️ get-size v2
• 🍹 switch out Grunt for Gulp for tasks