optimize png images losslessly using zopflipng

[PeterDaveHello]

Using Google's zopflipng to optimized the png images!

 demos/autocomplete/images/jquery_32x32.png        | Bin 1417 -> 1331 bytes
 demos/autocomplete/images/jqueryui_32x32.png      | Bin 1189 -> 1150 bytes
 demos/autocomplete/images/sizzlejs_32x32.png      | Bin 997 -> 965 bytes
 demos/autocomplete/images/transparent_1x1.png     | Bin 81 -> 68 bytes
 demos/checkboxradio/images/jquery-mobile.png      | Bin 6296 -> 4041 bytes
 demos/checkboxradio/images/jquery-ui.png          | Bin 7044 -> 4467 bytes
 demos/checkboxradio/images/jquery.png             | Bin 7206 -> 4507 bytes
 demos/checkboxradio/images/qunit.png              | Bin 6740 -> 4354 bytes
 demos/checkboxradio/images/sizzle.png             | Bin 8875 -> 6223 bytes
 demos/selectmenu/images/24-podcast-square.png     | Bin 681 -> 395 bytes
 demos/selectmenu/images/24-rss-square.png         | Bin 594 -> 390 bytes
 demos/selectmenu/images/24-video-square.png       | Bin 649 -> 491 bytes
 tests/images/jquery_521x191.png                   | Bin 3894 -> 3866 bytes
 tests/images/jqueryui_32x32.png                   | Bin 1193 -> 1150 bytes
 tests/visual/effects/image.png                    | Bin 3894 -> 3866 bytes
 themes/base/images/ui-bg_flat_0_aaaaaa_40x100.png | Bin 180 -> 86 bytes
 themes/base/images/ui-icons_444444_256x240.png    | Bin 6992 -> 3756 bytes
 themes/base/images/ui-icons_555555_256x240.png    | Bin 6988 -> 3756 bytes
 themes/base/images/ui-icons_777620_256x240.png    | Bin 4549 -> 3756 bytes
 themes/base/images/ui-icons_777777_256x240.png    | Bin 6999 -> 3756 bytes
 themes/base/images/ui-icons_cc0000_256x240.png    | Bin 4549 -> 3756 bytes
 themes/base/images/ui-icons_ffffff_256x240.png    | Bin 6299 -> 3756 bytes

[mention-bot]

By analyzing the blame information on this pull request, we identified @arschmitz, @scottgonzalez and @pereorga to be potential reviewers