Add nodes.node_types
Implement some filtering functions (not tested and documented)
Implement show pipes (not tested and documented)
Fix bug in keyword specification
Add project filtering
Add filter pipe
Write docstrings
Add test
Enable to specify multiple projects
Bug fix (show_runs accept multiple projects)
Revise description: s/name/path/
Merge pull request #114 from termoshtt/show_pipes

Show pipes
Add document.
Update docstring.