SHOW CREATE TABLE using table protobuf message

… and really testing the replication code path for CREATE TABLE.

So, for a very long time now, Drizzle has been using a protobuf based structure to describe the structure of tables. The idea was to be able to have engines rather painlessly generate this structure themselves (which several now do). A secondary idea was to use this structure itself for CREATE TABLE (in progress, and embedded_innodb does in fact does only use the table message for its CREATE TABLE codepath). The third idea was to just put the table protobuf message into the replication stream instead of the CREATE TABLE statement (i.e. a SQL string). This means that you could (easily) write a replicator to a DBMS with different SQL syntax, or to a system that doesn’t speak SQL at all.

The final step, to reduce duplicated code functionality, would be to have the code that does SHOW CREATE TABLE to use a common bit of code for turning a table protobuf message back into a SQL string.

We now have that.

Just now, my branch to replace the old SHOW CREATE TABLE code (that was using TableShare and friends) with the statement_transform code (that we also use in converting a replication log to SQL commands) hit trunk.