Remove pipes which does not support new node_list format.
Skip duplicate node.
Compliment parents and chilren list of origin node_list.
Modify doctest.
Merge pull request #19 from marubu/duplicate_scan

Duplicate scan
Merge pull request #18 from kenbeese/cleaning

Cleaning
Resolved namespace.
Make json files readable.
Bug fixed
Merge pull request #24 from kenbeese/bug-fixed

Bug fixed
Merge pull request #21 from kenbeese/unfound-exception

Unfound exception
Merge pull request #22 from kenbeese/readable-jsonfile

Readable jsonfile