message: Fixing Travis badge: report master branch status
diff: -[![TravisCI build status (Linux)](https://travis-ci.org/ispc/ispc.svg?branch=travis)](https://travis-ci.org/ispc/ispc)
  +[![TravisCI build status (Linux)](https://travis-ci.org/ispc/ispc.svg?branch=master)](https://travis-ci.org/ispc/ispc)
  [![Appveyor build status (Windows)](https://ci.appveyor.com/api/projects/status/xfllw9vkp3lj4l0v/branch/master?svg=true)](https://ci.appveyor.com/project/ispc/ispc/branch/master)
  Intel(r) SPMD Program Compiler
  