[vtkusers] vtkFLTK 0.4.5 quality update release

[Sean McInerney]

The 0.4.5 release of vtkFLTK eliminates annoying improper redrawing of 
sibling widgets upon parent resize. This was the last of the known 
runtime bugs experienced with vtkFLTK and represents a major milestone 
for the quality of the library. Additionally, release 0.4.5 addresses 
some minor backwards compatibility issues with the CMake build system 
and provides a fun new demo program based on VTK's Canny edge detection 
example.

-Sean