Blender exporter : changed object.isVisible to reflect the corresponding param in Blender (show/hide object to camera in render view button)

Also incremented the "not been changed for a while" version number of the exporter (more convenient to know which version is actually installed in blender ;-p)
Merge pull request #208 from vousk/dev_blender

Blender exporter : changed object.isVisible to reflect the corresponding...