DRILL-604: Add schema type to INFORMATION_SCHEMA.SCHEMATA.

Modification for SubSchemaWrapper.
DRILL-635: Fix run-time code generation bug for case expression, when the holder of return type does not have value field.
DRILL-700: Extend AvaticaDrillSqlAccessor to support getDate(), getTime() and getTimestamp()

 + Added accessor methods for getDate(), getTime() and getTimeStamp() in each of the data type's accessor class.
DRILL-718: Return complex types as JSON string.