Bug fix for translation class, DB IO connection error set fix

- The translation file reader did an isset on a set variable insetad of
checking if the variable is zero and so never started the translation
system
- The DB IO connection not set was wrongly set. If the connection failed
it is not TRUE and else FALSE. There is a new internal method
getConnectionStatus to query this status it returns TRUE/FALSE depending
if the connection failed

- Update the l10n test page with proper translation tests
  - init OK
  - show current lang/file
  - translation test
  - switch language test

www/lib/CoreLibs/DB/IO.php

@@ -376,18 +376,15 @@ class IO extends \CoreLibs\Basic
 			// abort error
 			$this->error_id = 10;
 			$this->__dbError();
-			$this->db_init_error = false;
+			$this->db_init_error = true;
 		}
 
 		// connect to DB
 		if (!$this->__connectToDB()) {
 			$this->error_id = 16;
 			$this->__dbError();
-			$this->db_init_error = false;
+			$this->db_init_error = true;
 		}
-
-		// so we can check that we have a successful DB connection created
-		$this->db_init_error = true;
 	}
 
 	/**
@@ -897,6 +894,17 @@ class IO extends \CoreLibs\Basic
 		}
 	}
 
+	/**
+	 * returns the db init error
+	 * if failed to connect it is set to true
+	 * else false
+	 * @return bool connection failure status
+	 */
+	public function getConnectionStatus(): bool
+	{
+		return $this->db_init_error;
+	}
+
 	/**
 	 * sets new db schema
 	 * @param  string $db_schema schema name, if not given tries internal default db schema