Adding name as a positional argument to pipeline classes
Updating CHANGES
STY: PEP8 in pipeline engine
Also making iterfield positional in MapNode
Reversing the order of the name and iterfield args in MapNode
Updating pipeline docstrings
base_dir in Workflow
Updating CHANGES
Merge pull request #601 from mwaskom/enh/pipeline_names

name as a positional argument for Workflow and (Map)Node