Add add_node pipe.
Add test of add_node.
Update test.
Minor fix according to the review.
Merge pull request #112 from kenbeese/add-node

Add node
Update test utility.
Update test.
Hot fixed.
Adopt to the case when configure file does not exist

- don't force the existence of ~/.dataprocessor.ini
- remove create_configure_file
- refactoring
Add configure creator (dpinit)
Enable piping in dpmanip