code: function executeAll (cfg) {
      console.log(`${clr.DIM+clr.LIGHT_MAGENTA}Package: ${cfg.packageRoot}${clr.RESET}`);
      return new Promise((resolve, reject) => {
          createObservable(cfg).subscribe({
              next ({command, exitCode}) {
                  if (exitCode == 0)
                      cfg.log(`${EMIT_COLOR}just-build ${cfg.tasksToRun.join(' ')}`+
                              ` done.${clr.RESET}${cfg.watchMode ? NOW_WATCHING_COLOR+' Still watching...'+clr.RESET : ''}`);
                  else 
                      cfg.log(`just-build ${cfg.tasksToRun.join(' ')} failed. ${command} returned ${exitCode}`);
              },
              error (err) {
                  reject(err);
              },
              complete () {
                  resolve();
              }                
          });
      });
  }
docs: Execute the build tasks.
  
  @param cfg {{
  dir: string,
  taskSet: Object.<string, string[]>,
  tasksToRun: string[],
  watchMode: boolean,
  spawn: Function,
  env: Object,
  log: Function,
  packageRoot: string
  }} Configuration to execute
  @return Promise