ignore null values in createWith
ignore null values in createWith

From the Neo4j docs: NULL is not a valid property value. NULLs can
instead be modeled by the absence of a key. So we’ll just ignore the
keys when they occur.

sgpatil/NeoEloquent,DenisGold/NeoEloquent,andrewdalpino/NeoEloquent,tomb10516/NeoEloquent,geminixxl/NeoEloquent,pchaow/NeoEloquent,logikinc/NeoEloquent,togusafish/logikinc-_-NeoEloquent