v0.1.5 - add switch-control component

• NEW: switch-control element
  is deigned specifically for single-button
  toggle switches.
  • Supports both data-on and data-off attributes
  • Pass functions to the
    onPress() and onUnPress() methods
    for additional behaviors
• NEW: switch-control.css provides
  styling for any button[is-switch],
  along with custom properties for styling.
• NEW: GroundControl provides
  a getter for inputId
  (previously only a setter).
• BREAKING: The usedValue getter
  defined by GroundControl
  does not enforce an empty-string fallback.
  Instead, attributes/properties are removed
  when usedValue is undefined.
• BREAKING: GroundControl provides
  static blockDisplay() method,
  rather than applying display:block by default.
  Both toggle-control and input-control
  apply this as a default setting,
  but switch-control does not.