Blender Git Loki

Freestyle: Fix for a potential infinite loop in stroke resampling by vertex count.

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.