Added a common database backend implementation.

Added sqlite (proof of concept)

persistence/implementation/sqlite/tests/util/abstract_db_test.e

@@ -0,0 +1,19 @@
+note
+	description: "Summary description for {ABSTRACT_DB_TEST}."
+	date: "$Date$"
+	revision: "$Revision$"
+
+class
+	ABSTRACT_DB_TEST
+
+
+feature -- Database connection
+
+	connection: DATABASE_CONNECTION_ODBC
+			-- odbc database connection
+		once
+--			create Result.login_with_connection_string ("Driver=SQLite3 ODBC Driver;Database=PATH/SQLITE.FILE;LongNames=0;Timeout=1000;NoTXN=0;SyncPragma=NORMAL;StepAPI=0;")
+			create Result.make_basic ("cms_dev")
+		end
+
+end