Fix strange bugs when limits are wrongly set.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@3611 dfc29bdd-3216-0410-991c-e03cc46cb475

source/Irrlicht/CGUISpinBox.cpp

@@ -129,6 +129,8 @@ f32 CGUISpinBox::getValue() const
 
 void CGUISpinBox::setRange(f32 min, f32 max)
 {
+	if (max<min)
+		core::swap(min, max);
 	RangeMin = min;
 	RangeMax = max;
 	verifyValueRange();