Add add_node pipe.
Add test of add_node.
Update test.
Add DataHandler.update
Implement rc.py
Add document
Raise DataProcessorError when configure file does not exist
Omit get_*_dir (will be included into dpstart PR)
Update documents
Update document.
Merge pull request #116.
Minor fix according to the review.
Merge pull request #112 from kenbeese/add-node

Add node
Update test utility.
Update test.
Add move_node.py
Add register function.
Refactoring.
Add filter.prefix_path and its test.
Add move_node pipe.