Move create{Node,Relationship} over to the Kernel API.

As of this change all mutating operations have moved over to the
Kernel API, getRelationships(*) still remain in the NodeImpl.
These are not as "dangerous" to be able to mix with Schema operations
so they can wait another short while.
Merge pull request #1133 from thobe/2.0-schema-and-data-tx-for-create-node-and-relationship

Move create{Node,Relationship} over to the Kernel API.
Fixed error where data corruption occured if indexing node with multiple labels in multiple indexes using batch inserter.
Remove unused class.

Uses were removed when kernel loopholes were cleaned up.
Merge pull request #1138 from jakewins/batch-bork

Fixes index corruption in batch inserter
Reverting UnboundValue and OptionalsPipe
Change commands.Pattern to use objects for Node representation instead of a string
Added optionality to nodes on the AST object
Added functionality to infer and mark nodes as optional