Adds logging of schema index startup
Tests the startup logging performed by IndexingService.

o IndexingService logs the state of all indexes on init and start.
o IndexPopulationJob logs failure to populate an index.
Fix for a concurrency issue in StatementContextOwner

Kernel had a single StatementContextOwner instance which was shared among
all threads accessing read-only statement contexts, and yet the
StatementContextOwner didn't consider concurrency.

Added a test case showing the problem as well as a fix in Kernel where a
ThreadLocal<StatementContextOwner> is used instead of a single StatementContextOwner.
Merge pull request #669 from tinwelint/stmt-ctx-owner-concurrency

Fix for a concurrency issue in StatementContextOwner
Merge pull request #667 from boggle/logging-index-startup

Adds logging of schema index startup
Work in progress
First working test
Add string literals in return
Add NODE(*) matching
Add result col renaming and number results
format
Allow inference of Rule0
Add index lookups and queries
Split parser into multiple traits
Reformat
Add expression calculator
Add WHERE clause and property equality predicate
Add decimal literals
Add NOT and <>
Add <, >, <= and >=