Add unary - and unary + to cypher parser

Resolves #1213
Lucene label scan store can be used in batch insertion

This fixes a problem where the LuceneLabelScanStore couldn't be used in
batch insertion due one of its dependencies (Dependencies#getLogging())
couldn't be resolved by the batch inserter's dependency resolver. Tests
didn't catch this since the test-only in-memory label scan store was
selected instead due to being available.
Merge pull request #1214 from cleishm/unary_plus_minus

Add unary - and unary + to cypher parser
fixing null values in literal maps blowing up
Merge pull request #1228 from neo4j/literalmapnulls

fixing null values in literal maps blowing up
Merge pull request #1221 from tinwelint/2.0-lucene-labelscanstore-it

Lucene label scan store can be used in batch insertion
Fix for inability to remove constraints in HA.

 o Added test that verifies database does not block writes while populating constraint index.
 o Verifies that constraint deletion works in HA clusters.
 o Added test to verify new slave joining cluster properly initializes constraints
 o Added before/after records for schema commands to allow deleting schema rules from
   logical log.