Updated Travis config to install ubuntu-restricted-extras to enable mp4 / mp3 encoding
Updated Travis config to install ubuntu-restricted-extras to enable mp4 / mp3 encoding

jdn06/sigal,franek/sigal,saimn/sigal,cbosdo/sigal,t-animal/sigal,t-animal/sigal,xouillet/sigal,xouillet/sigal,saimn/sigal,saimn/sigal,Ferada/sigal,elaOnMars/sigal,jdn06/sigal,kontza/sigal,kontza/sigal,xouillet/sigal,kontza/sigal,Ferada/sigal,cbosdo/sigal,jasuarez/sigal,t-animal/sigal,cbosdo/sigal,franek/sigal,jasuarez/sigal,Ferada/sigal,jdn06/sigal,jasuarez/sigal,elaOnMars/sigal