Selectivity 3.0.0-rc1

• Made jQuery dependency fully optional.
  • As a result, all callbacks that received jQuery containers as argument(s) now receive plain DOM
    nodes instead.
• Added optional React API.
• Fix #128: Added NPM package.
• Added options:
  • shouldOpenSubmenu() - Callback that determines whether a submenu should be opened.
  • selectable - Allows to make items unselectable without having to disable them. This is mainly
    useful for items that trigger submenus.
• Removed Bower and Component support.
• Moved option validation into its own plugin.
• Rewrote the AJAX plugin:
  • It now relies on the fetch() method for performing AJAX requests. This method is only
    available on modern browsers, so you'll need a polyfill if you want to use this with old
    browsers, unless you're using a jQuery build in which case the jquery/ajax plugin can provide
    a shim based on $.ajax() (requires jQuery 3.0 or higher).
  • Please check the documentation for the new options that can be passed.
• Renamed the option suppressMouseWheelSelector to just suppressWheelSelector.
• Renamed the Selectivity.InputTypes map to Selectivity.Inputs.
• Removed dist directory from the repository.
• Improved submenu positioning by automatically opening them on the left-hand side if there's
  insufficient space on the right side.
• Improve searching behavior with multiple submenus open.
• Fix #107: Remove the dropdown after timeout to fix "hover" behavior.
• Fix #136: Update original <select> element on "change" instead of "selectivity-selected".
• Fix: When a Selectivity instance is clicked but its dropdown should not open, at least it should
  be focused.
• Fix #144: Properly handle dynamically changing readOnly option.
• Fix #145: Make sure size detection works outside the DOM (thanks to @Rkokie). Also the
  ".selectivity-width-detector" element is no longer needed.
• Fix #146: Selectivity created from <select> element now uses "s9y_" prefix for its ID (thanks to
  @dr-itz).
• Fix: Provide correct offset in pagination when results are filtered.