Add master branch to travis build
Add master branch to travis build

anshuarya/OpenSubdiv,xldeveloper/OpenSubdiv,lookup1980/OpenSubdiv,c64kernal/OpenSubdiv,nyotis/OpenSubdiv,takahito-tejima/OpenSubdiv,nyotis/OpenSubdiv,lookup1980/OpenSubdiv,shengfuintel/OpenSubdiv,c64kernal/OpenSubdiv,takahito-tejima/OpenSubdiv,shengfuintel/OpenSubdiv,nyotis/OpenSubdiv,lookup1980/OpenSubdiv,xldeveloper/OpenSubdiv,anshuarya/OpenSubdiv,c64kernal/OpenSubdiv,takahito-tejima/OpenSubdiv,shengfuintel/OpenSubdiv,anshuarya/OpenSubdiv,xldeveloper/OpenSubdiv