Check and create tables on start up

[holic]

CREATE TABLE IF NOT EXISTS `MiracleGrow_world_blocks` (
    `x` smallint(6) NOT NULL DEFAULT '0',
    `y` tinyint(4) NOT NULL DEFAULT '0',
    `z` smallint(6) NOT NULL DEFAULT '0',
    `type` smallint(6) DEFAULT NULL,
    `data` tinyint(4) DEFAULT NULL,
    PRIMARY KEY (`x`,`y`,`z`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `MiracleGrow_world_jobs` (
    `x` smallint(6) NOT NULL DEFAULT '0',
    `y` tinyint(4) NOT NULL DEFAULT '0',
    `z` smallint(6) NOT NULL DEFAULT '0',
    `chunk_x` smallint(6) NOT NULL DEFAULT '0',
    `chunk_z` smallint(6) NOT NULL DEFAULT '0',
    `when` timestamp NULL DEFAULT NULL,
    `job` int(11) DEFAULT NULL,
    `updated` timestamp NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    PRIMARY KEY (`x`,`y`,`z`),
    INDEX `when` (`when`),
    INDEX `job` (`job`),
    INDEX `x` (`x`),
    INDEX `y` (`y`),
    INDEX `z` (`z`),
    INDEX `chunk_x` (`chunk_x`),
    INDEX `chunk_z` (`chunk_z`),
    INDEX `chunk_xz` (`chunk_x`,`chunk_z`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;