fix(index): set maxConcurrentCallsPerWorker to 1 (options.parallel) (#173)

* fix: set workerFarm maxConcurrentCallsPerWorker to 1 to allow Windows parallel builds

* fix: Missing trailing comma lint error

* fix(index): make maxConcurrentCallsPerWorker limit windows only

Author: brentwilton

Diff for: src/uglify/index.js

@@ -26,9 +26,8 @@ export default class {
     }
 
     if (this.maxConcurrentWorkers > 0) {
-      this.workers = workerFarm({
-        maxConcurrentWorkers: this.maxConcurrentWorkers,
-      }, workerFile);
+      const workerOptions = process.platform === 'win32' ? { maxConcurrentWorkers: this.maxConcurrentWorkers, maxConcurrentCallsPerWorker: 1 } : { maxConcurrentWorkers: this.maxConcurrentWorkers };
+      this.workers = workerFarm(workerOptions, workerFile);
       this.boundWorkers = (options, cb) => this.workers(JSON.stringify(options, encode), cb);
     } else {
       this.boundWorkers = (options, cb) => {