Issue #3300800 by mvogel: Updating SpinKit CSS Library

css/chasing-dots.css

css/circle.css

css/cube-grid.css

css/double-bounce.css

css/fading-circle.css

css/folding-cube.css

css/pulse.css

css/rotating-plane.css

css/swing.css

css/three-bounce.css

css/throbber-general.css

css/wandering-cubes.css

css/wave.css

src/Plugin/ajax_loader/ThrobberChasingDots.php

src/Plugin/ajax_loader/ThrobberCircle.php

src/Plugin/ajax_loader/ThrobberCubeGrid.php

src/Plugin/ajax_loader/ThrobberDoubleBounce.php

src/Plugin/ajax_loader/ThrobberFadingCircle.php

src/Plugin/ajax_loader/ThrobberFoldingCube.php

src/Plugin/ajax_loader/ThrobberPulse.php