Demos/tests: Losslessly recompress PNG/GIF images.

9185 saved compressing these files losslessly.

-4	demos/autocomplete/images/jqueryui_32x32.png
-2	demos/autocomplete/images/sizzlejs_32x32.png
-14	demos/autocomplete/images/transparent_1x1.png
-11	demos/datepicker/images/calendar.gif
-11	demos/images/calendar.gif
-4566	demos/images/pbar-ani.gif
-4566	demos/progressbar/images/pbar-ani.gif
-11	tests/unit/datepicker/images/calendar.gif