DocBlocks for base DB classes

Partially fixes issue #1295.
diff --git a/system/database/DB_utility.php b/system/database/DB_utility.php
index 12680be..3bd77c8 100644
--- a/system/database/DB_utility.php
+++ b/system/database/DB_utility.php
@@ -35,13 +35,31 @@
  */
 abstract class CI_DB_utility extends CI_DB_forge {
 
+	/**
+	 * Database object
+	 *
+	 * @var	object
+	 */
 	public $db;
 
-	// Platform specific SQL strings
-	// Just setting those defaults to FALSE as they are mostly MySQL-specific
+	// --------------------------------------------------------------------
+
+	/**
+	 * OPTIMIZE TABLE statement
+	 *
+	 * @var	string|bool
+	 */
 	protected $_optimize_table	= FALSE;
+
+	/**
+	 * REPAIR TABLE statement
+	 *
+	 * @var	string|bool
+	 */
 	protected $_repair_table	= FALSE;
 
+	// --------------------------------------------------------------------
+
 	/**
 	 * Constructor
 	 *
@@ -95,7 +113,7 @@
 	/**
 	 * Determine if a particular database exists
 	 *
-	 * @param	string
+	 * @param	string	$database_name
 	 * @return	bool
 	 */
 	public function database_exists($database_name)
@@ -108,7 +126,7 @@
 	/**
 	 * Optimize Table
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table_name
 	 * @return	mixed
 	 */
 	public function optimize_table($table_name)
@@ -169,7 +187,7 @@
 	/**
 	 * Repair Table
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table_name
 	 * @return	mixed
 	 */
 	public function repair_table($table_name)
@@ -194,10 +212,10 @@
 	/**
 	 * Generate CSV from a query result object
 	 *
-	 * @param	object	The query result object
-	 * @param	string	The delimiter - comma by default
-	 * @param	string	The newline character - \n by default
-	 * @param	string	The enclosure - double quote by default
+	 * @param	object	$query		Query result object
+	 * @param	string	$delim		Delimiter (default: ,)
+	 * @param	string	$newline	Newline character (default: \n)
+	 * @param	string	$enclosure	Enclosure (default: ")
 	 * @return	string
 	 */
 	public function csv_from_result($query, $delim = ',', $newline = "\n", $enclosure = '"')
@@ -234,8 +252,8 @@
 	/**
 	 * Generate XML data from a query result object
 	 *
-	 * @param	object	The query result object
-	 * @param	array	Any preferences
+	 * @param	object	$query	Query result object
+	 * @param	array	$params	Any preferences
 	 * @return	string
 	 */
 	public function xml_from_result($query, $params = array())
@@ -281,7 +299,7 @@
 	/**
 	 * Database Backup
 	 *
-	 * @param	array	$params = array()
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function backup($params = array())
@@ -294,8 +312,6 @@
 			$params = array('tables' => $params);
 		}
 
-		// ------------------------------------------------------
-
 		// Set up our default preferences
 		$prefs = array(
 				'tables'		=> array(),