Blender Git Loki

* Fix for a freeze issue in stroke rendering when using round/square caps.
The problem was caused by a stroke with only one vertex. Such a stroke was
generated when for some unknown reason a chained curve consisted of only
two vertices such that their 3D positions were exactly or almost the same.

* Fix for the Parameter Editor mode that failed when scene render layers
and/or linesets contain a single quote in their names.