Neomodel

* server compatability check (Robin Edwards)
* 1.9 server fixes (Robin Edwards)
* upgrade to py2neo 1.6.1 (Panos Katseas)
* make __index__ inherited (Sebastian Ortiz)
* documentation improvements (Priit Laes)
* import RelationshipDefinition and RelationshipManager into main

* Display nice message for operations on deleted node (Robin Edwards)
* Re-enable lucene-querybuilder (Robin Edwards)
* Fix X-Stream header (Nigel Small)
* Enable custom indexes for StructuredNodes
* Support for relationship models or 'StructuredRels'
* Support filtering in the 'traverse' method (Robin Edwards)
* Store datetime objects as float for more accuracy (Robin Edwards)
* Setup NEOMODEL_FORCE_TIMEZONE env var to prevent storing of datetimes
without a timezone (Robin Edwards)
* Add NEOMODEL_CYPHER_DEBUG env var to log querys (Robin Edwards)
* Relative relationship classes in definitions (Panos Katseas)

* Add documentation on batch size (Robin Edwards)
* Fix default_value type generation for basic properties 53
* Add documentation on providing arguments to default functions (Robin Edwards)

* Fix return > 1 for Localised (Marianna Polatoglou)

* Nice exception on missing search params (Robin Edwards)

* Property fixes (Laurie Clark-Michalek)