Compound(map-like) properties implementation. Needs neo team review

Hi all!
I've implemented compound (map-like) property support.

Implementation supports map property values of unconstrained nesting depth.
Implementations does NOT support arrays of maps (neither as direct node property nor as nested map property) for this moment.

Implementation needs more tests (including batch insertion tests), but for now I want to ask neo4j team to review this implementation and to leave thoughts and comments.

Also see topic https://groups.google.com/forum/?fromgroups=#!searchin/neo4j/compound/neo4j/s8_YhLQpPEY/TwAURcv3Of0J