Fixes broken syntax in docs.
Close statement context in correct finally block.
Rename StatusCode.STATEMENT_MISSING_PARAMETER.
Add test case for failing to create constrain over duplicate data.
Move index-related kernel exceptions into their own package.

org.neo4j.kernel.api.exceptions.index package sits alongside equivalent schema package.
Add license header.
Start of moving Primitive#*property stuff and caching into kernel API

o Introduced AuxStoreOps
o Integration between PropertyData and Property
o Merged the two caches so that NodeImpl/RelationshipImpl is used for all
caching, even for labels. Closing in on a complete move.
Plugs in legacy auto-indexing into the KernelAPI
Makes sure PropertyData#getId() isn't use as it cannot be trusted anymore
Missing store file throws specific exception so that it can be treated the same way as a mismatching store version... namely to try and upgrade