Implement latch VARCHAR()- query works with good string names, but partially for string'd numbers, and not for null or cast numbers

Implement latch VARCHAR()- table structure - retain SHORTINT backwards compatibility. Passes test for b/compat

Adding social test suite

Added oqgraph "create attr" test as per Andrew's regression test. Fixups required before we can record results.

Updated oqgraph copyright, version and author info.

Make sure that boost is included with consistent config.

MDEV-3997: Querying a Cassandra table on a server with query cache enabled is likely to cause problems
- Disable query cache for Cassandra tables.

my_alloca() cannot have MY_THREAD_SPECIFIC, because can be used
outside of the THD context.

when no ha_example.so is built

Add a wait for binlog checkpoint to avoid thread scheduling
giving different binlog order at random.