message: Create output directory and sub directories on build
diff: import * as vscode from 'vscode'
  import * as path from 'path'
  -import * as fs from 'fs'
  +import * as fs from 'fs-extra'
  import * as cp from 'child_process'
  import {Extension} from '../main'
  @@ -52,6 +52,17 @@ export class Builder {
  this.disableCleanAndRetry = false
  this.extension.logger.displayStatus('sync~spin', 'statusBar.foreground')
  this.preprocess(rootFile)
  +
  + // Create sub directories of output directory
  + if (this.extension.manager.getOutputDir(rootFile) !== './') {
  + const directories = new Set<string>(this.extension.manager.watched
  + .map(file => path.dirname(file.replace(this.extension.manager.rootDir, ''))))
  + const outputDir = path.join(this.extension.manager.rootDir, this.extension.manager.getOutputDir(rootFile))
  + directories.forEach(directory => {
  + fs.ensureDirSync(path.join(outputDir, directory))
  + })
  + }
  +
  if (this.nextBuildRootFile === undefined) {
  this.buildInitiator(rootFile, recipe)
  }
  