Option to turn off cache busting

It would be good to be able to turn off cache busting hashes.
Something like:

```
compiler.js line 189:

    var hashedFilename = path.basename(filePath) + '?' + hash(filePath + content)

>>>

  if(options.bustCaches === true) {
    var hashedFilename = path.basename(filePath) + '?' + hash(filePath + content)
  }

```