Revert back to yui compressor 2.4.7
Revert back to yui compressor 2.4.7

Because version 2.4.8 of yui compressor has not yet been integrated into the project (due to a couple of bugs), we need to continue using version 2.4.7 for the time being.
fady/ant-build-script,h5bp/ant-build-script,firnny29-cts/helloworld1