message: only write the package.json if it's travis
diff: @@ -31,7 +31,10 @@ if (semver.gt(packageObj.version, version)){
  console.log(`incrementing to version ${version}`);
  packageObj.version = version;
  +//only if it's travis, update the package.json
  +if (process.env.TRAVIS){
  fs.writeFileSync(packageFile, JSON.stringify(packageObj, undefined, " "));
  +}
  //write a version file
  var versionFile = `module.exports = ${JSON.stringify({ version, dev : isDev }, undefined, "\t")};\n`;
  