Optimized the setup (not only), shortened to 37s (used to be 120s)

- DBObject::DBInsert(Tracked)NoReload() must be used when it is not required to use the object
- MetaModel::GetObject() has a cache, the operation is 5 times faster
- Changes tracking do not store the initial value, but only value changes
Reworked the CSV import to have it rely on the bulk change API
Bulk change to check the external keys (DB integrity)
Replaced trigger_error (Core only!) by the use of Exceptions (still, some new Exception classes should be defined)
Unit tests do display the call stack in a user friendly format

SVN:code[52]

application/dialogstack.class.inc.php

@@ -122,7 +122,7 @@ class dialogstack
 
 		if (self::$m_bCurrPageDeclared)
 		{
-			trigger_error("DeclareCaller() must not be called before StartDialog()", E_USER_ERROR);
+			throw new Exception("DeclareCaller() must not be called before StartDialog()");
 		}
 
 		$aCall = array(
@@ -242,7 +242,7 @@ class dialogstack
 		}
 		else
 		{
-			trigger_error("Wrong value for button style ($iButtonStyle)", E_USER_ERROR);		
+			throw new Exception("Wrong value for button style ($iButtonStyle)");		
 		}
 		$sRet .= "<input type=\"hidden\" name=\"dialogstackpop\" value=\"".count($_SESSION['dialogstack_currdlg'])."\">\n";
 		$sRet .= "</form>\n";