Add build badge to README.
Add build badge to README.

madjam/copycat,kuujo/copycat,tempbottle/copycat,kuujo/copycat,arnonmoscona/copycat,arnonmoscona/copycat,madjam/copycat,tempbottle/copycat,atomix/atomix,aruanruan/copycat,atomix/atomix,aruanruan/copycat