[PD] fix property issues

- Helix: the property Turns has the App::PropertyFloatConstraint thus also the pointer to it must have the same property

- LinearPattern and Helix: make constraints static class member (forgot this in commit 3704ad68)

- Draft: make the constraint const

- PolarPattern and LinearPattern assure that the header file is loaded at last to avoid potential troubles

src/Mod/PartDesign/App/FeatureHelix.cpp

@@ -72,8 +72,8 @@ const char* Helix::ModeEnums[] = {"pitch-height-angle", "pitch-turns-angle", "he
 PROPERTY_SOURCE(PartDesign::Helix, PartDesign::ProfileBased)
 
 // we purposely use not FLT_MAX because this would not be computable
-const App::PropertyFloatConstraint::Constraints floatTurns = { Precision::Confusion(), INT_MAX, 1.0 };
-const App::PropertyAngle::Constraints floatAngle = { -89.0, 89.0, 1.0 };
+const App::PropertyFloatConstraint::Constraints Helix::floatTurns = { Precision::Confusion(), INT_MAX, 1.0 };
+const App::PropertyAngle::Constraints Helix::floatAngle = { -89.0, 89.0, 1.0 };
 
 Helix::Helix()
 {