[MeL] Make Properties::hasPropertyVector() const.

MeshLib/Properties.cpp

@@ -30,7 +30,7 @@ void Properties::removePropertyVector(std::string const& name)
 	_properties.erase(it);
 }
 
-bool Properties::hasPropertyVector(std::string const& name)
+bool Properties::hasPropertyVector(std::string const& name) const
 {
 	std::map<std::string, PropertyVectorBase*>::const_iterator it(
 		_properties.find(name)

MeshLib/Properties.h

@@ -98,7 +98,7 @@ public:
 	/// Check if a PropertyVector accessible by the name is already
 	/// stored within the Properties object.
 	/// @param name the name of the property (for instance porosity)
-	bool hasPropertyVector(std::string const& name);
+	bool hasPropertyVector(std::string const& name) const;
 
 	std::vector<std::string> getPropertyVectorNames() const;