Clean code
example: Remove ugly tests
Fix createDir

Now handles creating already-existing directories.

This can happen in asynchronous mode.
Returns (and show) generation errors

The gulp command displays them and other tools
are now able to know if the generation as been
successful of if there were errors.
Merge branch 'return-errors' into next

* return-errors:
  Returns (and show) generation errors
  Fix createDir
  example: Remove ugly tests
  Clean code