remove dependency on distutils

[satra]

let's see if we can remove distutils dependencies

DEPRECATION: Uninstalling a distutils installed project (nipype) has been deprecated 
and will be removed in a future version. This is due to the fact that uninstalling a 
distutils project will only partially uninstall the project.

[oesteban]

I'm working on this here https://github.com/oesteban/nipype/tree/enh/MigrateToSetuptools