Fix memory leak for HeaderEntity instances:

the getArgumentCount() call in IfcEntityInstanceData destructor isn't virtually dispatched so it returns 0 instead of correct number of arguments => memory leak
added IfcEntityInstanceData::clearArguments() which clears all arguments and resets the attributes_ field to nullptr

Remove unnecessary copy in IfcEntityInstanceData::setArgument() when argument is created at the call site (no more leak of original argument)

Fix memory leak in IfcFile: delete entities from both byid and entity_file_map

src/ifcparse/IfcSpfHeader.cpp

@@ -46,6 +46,10 @@ HeaderEntity::HeaderEntity(const char * const datatype, size_t size, IfcFile* fi
 	}
 }
 
+HeaderEntity::~HeaderEntity()
+{
+	clearArguments();
+}
 
 void IfcSpfHeader::readSemicolon() {
 	if (!TokenFunc::isOperator(file_->tokens->Next(), ';')) {