DDL statement throws error if compression keyword contains backticks (``)

For mysql dbs that use TokuDB, you can specify a compression type in the CREATE TABLE syntax.

The following would work as is:

CREATE TABLE foo ( c1 INTEGER NOT NULL ) engine=TokuDB compression=tokudb_zlib;

However the following would NOT work due to "compression" containing backticks which is completely valid syntax:

CREATE TABLE foo ( c1 INTEGER NOT NULL ) engine=TokuDB `compression`=tokudb_zlib;

Will be submitting a PR myself very shortly that seems to fix it though I'm a first time contributor and not extremely familiar with ANTLR so any review is much appreciated, thanks!