Add support for native point array properties

[Andy2003]

This introduces a new Encoder that allows to index native point arrays like this:

CREATE (node:Foo { points: [point({latitude: 5.0, longitude: 4.0}), point({latitude: 6.0, longitude: 5.0})]});

CALL spatial.addLayer('line','NativePoints','points') YIELD node
MATCH (n:Foo)
WITH collect(n) AS nodes
CALL spatial.addNodes('line', nodes) YIELD count RETURN count;

[craigtaverner]

Nice enhancement. I did have some suggestions though.