Changes were made in Stroke::Resample(int) in C++ to prevent a potential infinite loop caused by an inconsistency between Stroke::_Length and the stroke length computed based on stroke vertices. Such a stroke length inconsistency is usually caused by missing calls of Stroke::UpdateLength() (i.e., API implementation bugs), but also may occur due to scripting errors in user-defined style modules. This commit is meant to help script writters to identify the latter error cases. Now Stroke.resample(int) may raise a runtime error to signal an error condition.