initial stab at neo4j

[nathandunn]

not sure if we'll merge it, but good to have a placeholder here.

• do I need to do a simple mapping (start with a de no vo project?)
• get GORM mapped for startup (fix mapping errors as they come up)
• get tests to pass via python-apollo
• do performance tests

[nathandunn]

http://gorm.grails.org/latest/neo4j/manual/#combiningNeo4jAndHibernate

[nathandunn]

grails 4 + neo4j does not seem to be that stable