Make it work with other transforms

Apparently using workerify with other transforms (in my case aliasify) that change the process.cwd make workerify fail by associating a wrong path to the worker file.

In my case the process.cwd was pointing to the last fiel aliasify modified, instead of the file where you find workerify './path/to./worker'
Merge pull request #12 from rodincave/patch-1

Make it work with other transforms