Solve Bug 1318762 (launchpad)

1 - Converting named parameters to kwds (dict)
2 - Verify if "envp" is informed to add in kwds
3 - Call  glib.spawn_async with **kwds
4 - Add more debug info (argv, kwds, spawn result)

The best information I found about this bug.
http://stackoverflow.com/a/21793035