Fixed persistency layer.

Now we have ODBC .. that accepts various connection string (including SQLite, MySQL,...)
  And EiffelStore+MySQL.
Updated sql scripts to work with MySQL, and SQLite.
Added a sql_statement (s: STRING): STRING that converts ROC sql statement to fit the underlying database engine.
 mostly to adapt incompatibilities such as AUTO_INCREMENT for MySQL and AUTOINCREMENT for SQLite
 by default SQL script should be written following MySQL SQL syntax.
Warning: to use ODBC persistence driver, it has to be installed on the target machine.

examples/demo/site/scripts/node.sql

@@ -1,24 +1,22 @@
-BEGIN;
 
-CREATE TABLE "nodes" (
-	"nid"	INTEGER NOT NULL CHECK("nid" > 0) PRIMARY KEY AUTOINCREMENT UNIQUE,
-	"revision"	INTEGER,
-	"type"	TEXT NOT NULL,
-	"title"	VARCHAR(255) NOT NULL,
-	"summary"	TEXT,
-	"content"	TEXT,
-	"format"	VARCHAR(128),
-	"author"	INTEGER,
-	"publish"	DATETIME,
-	"created"	DATETIME NOT NULL,
-	"changed"	DATETIME NOT NULL,
-	"status"	INTEGER
+CREATE TABLE nodes (
+	`nid`	INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT UNIQUE,
+	`revision`	INTEGER,
+	`type`	TEXT NOT NULL,
+	`title`	VARCHAR(255) NOT NULL,
+	`summary`	TEXT,
+	`content`	TEXT,
+	`format`	VARCHAR(128),
+	`author`	INTEGER,
+	`publish`	DATETIME,
+	`created`	DATETIME NOT NULL,
+	`changed`	DATETIME NOT NULL,
+	`status`	INTEGER
 );
 
 CREATE TABLE page_nodes(
-  "nid" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL CHECK("nid">=0),
-  "revision" INTEGER,
-  "parent" INTEGER
+  `nid` INTEGER PRIMARY KEY AUTO_INCREMENT NOT NULL,
+  `revision` INTEGER,
+  `parent` INTEGER
 );
 
-COMMIT;