* Passes renamed to samples
* Camera lens radius renamed to aperature size/blades/rotation
* Glass and fresnel nodes input is now index of refraction
* Glossy and velvet fresnel socket removed
* Mix/add closure node renamed to mix/add shader node
* Blend weight node added for shader mixing weights
There is some version patching code for reading existing files, but it's not
perfect, so shaders may work a bit different.
* Add max diffuse/glossy/transmission bounces
* Add separate min/max for transparent depth
* Updated/added some presets that use these options
* Add ray visibility options for objects, to hide them from
camera/diffuse/glossy/transmission/shadow rays
* Is singular ray output for light path node
Details here:
http://wiki.blender.org/index.php/Dev:2.5/Source/Render/Cycles/LightPaths