[TD]add preference methods for center marks

src/Mod/TechDraw/App/Preferences.cpp

@@ -709,3 +709,13 @@ double Preferences::detailSnapRadius()
     return getPreferenceGroup("General")->GetFloat("DetailSnapRadius", 0.6);
 }
 
+
+bool Preferences::showCenterMarks()
+{
+    return getPreferenceGroup("Decorations")->GetBool("ShowCenterMarks", false);
+}
+
+bool Preferences::printCenterMarks()
+{
+    return getPreferenceGroup("Decorations")->GetBool("PrintCenterMarks", false);
+}