Let nipype work with python 2.6 again

This file runs even when importing nipype.interfaces.io, hence make
nipype unsuable without python 2.7
Merge pull request #625 from hanke/no_dict_comprh_in_2.6

Let nipype work with python 2.6 again
Merge pull request #626 from hanke/master

Update to DAGMan plugin
BF: Fix argument order for condor_submit_dag call

Previous setup did not allow for adding dagman_args as advertised.