A few minor changes in Lionfish

There have been added set_label and delete_label in
Python-based client. The old Python-based server has
been finally deleted.
Minor fixes
Merge branch lionfish into spidercrab
Lionfish: logging, refactoring

There has been added logging to Lionfish. A few
methods such as createRelationship have been
refactored.
Cypher -> Lionfish refactor part II
Merge branch lionfish into spidercrab