build script: quiet the optipng output
build script: quiet the optipng output

lhagan/PlainReader,scraperwiki/urchin-website,thetrickster/foundation-bc,lhagan/PlainReader,seanoshea/krissyoshea,seanoshea/krissyoshea,derekandtereza/derekandtereza.github.com,h5bp/ant-build-script,scraperwiki/urchin-website,lhagan/PlainReader,fady/ant-build-script,firnny29-cts/helloworld1,thetrickster/foundation-bc,jacquesdeklerk/jacquesdeklerk,thetrickster/foundation-bc,lhagan/PlainReader,jacquesdeklerk/jacquesdeklerk,lhagan/PlainReader,jacquesdeklerk/jacquesdeklerk,scraperwiki/urchin-website,derekandtereza/derekandtereza.github.com,thetrickster/foundation-bc