Add a new PropertyType enum Prop_NoRecompute to reduce possible inconsistencies between touched and recomputed features.

At the moment many feature classes lack of the mustExecute() method and thus can cause a touched feature not to be recomputed and causes the feature to be in a broken state.
Now this new enum value virtually makes the mustExecute() superfluous and thus guarantees to recompute a feature if a modified property has not set the Prop_NoRecompute flag.

On the other hand there are properties that should only touch a feature but not enforce a recompute. This guarantees a better performance and avoids unnecessary recomputes.
For example this is useful for placements where a change can be applied on-the-fly and the feature is up-to-date. Other features that depend on the touched feature will still be recomputed.

src/App/GeoFeature.cpp

@@ -42,7 +42,7 @@ PROPERTY_SOURCE(App::GeoFeature, App::DocumentObject)
 
 GeoFeature::GeoFeature(void)
 {
-    ADD_PROPERTY(Placement,(Base::Placement()));
+    ADD_PROPERTY_TYPE(Placement,(Base::Placement()),nullptr,Prop_NoRecompute,nullptr);
 }
 
 GeoFeature::~GeoFeature(void)