[TD]add preference re alpha/transparency conversion

src/Mod/TechDraw/App/Preferences.cpp

@@ -719,3 +719,10 @@ bool Preferences::printCenterMarks()
 {
     return getPreferenceGroup("Decorations")->GetBool("PrintCenterMarks", false);
 }
+
+
+//! true if old style transparency values should be converted to new style alpha values for color properties.
+bool Preferences::fixColorAlphaOnLoad()
+{
+    return getPreferenceGroup("General")->GetBool("FixColorAlphaOnLoad", true);
+}