added: the riot mixins tests to the karma config
added: the riot mixins tests to the karma config

scalabl3/riot,rthbound/riot,AndrewSwerlick/riot,davidmarkclements/riot,muut/riotjs,joshcartme/riot,qrb/riotjs,daemonchen/riotjs,baysao/riot,duongphuhiep/riot,beni55/riot,seedtigo/riot,qrb/riotjs,madlordory/riot,baysao/riot,txchen/riotjs,marcioj/riot,seedtigo/riot,zawsx/js-lib-webcomponents-react-riot,mike-ward/riot,xtity/riot,sylvainpolletvillard/riot,dschnare/riot,stonexer/riot,noodle-learns-programming/riot,daemonchen/riotjs,crisward/riot,chetanism/riot,AndrewSwerlick/riot,scalabl3/riot,duongphuhiep/riot,xtity/riot,joshcartme/riot,noodle-learns-programming/riot,beni55/riot,mike-ward/riot,davidmarkclements/riot,thepian/riot,dp-lewis/riot,tao-zeng/riot,madlordory/riot,zawsx/js-lib-webcomponents-react-riot,stonexer/riot,muut/riotjs,txchen/riotjs,thepian/riot,laomu1988/riot,laomu1988/riot,rasata/riot,dschnare/riot,crisward/riot,sylvainpolletvillard/riot,tao-zeng/riot,rthbound/riot,rasata/riot,chetanism/riot,dp-lewis/riot,marcioj/riot