MySQL fixes/additions/improvements

- fixed GH #187: MySQL: allow access to the underlying connection handle
- added GH #186: MySQL: support for MYSQL_SECURE_AUTH
- fixed GH #174: MySQL: 4GB allocated when reading any largetext or
largeblob field

Data/MySQL/testsuite/src/SQLExecutor.h

@@ -100,7 +100,7 @@ public:
 	void singleSelect();
 	void emptyDB();
 
-	void blob(int bigSize = 1024);
+	void blob(unsigned int bigSize = ~0);
 	void blobStmt();
 	void dateTime();
 	void date();