links updated

some renderman / RSL /OSL links added to my list:

thanks to Jimmy Gunawan and Michael Anders

http://accad.osu.edu/~smay/RManNotes/
http://michelanders.blogspot.com.au/p/creating-blender-26-python-add-on.htm
http://blenderthings.blogspot.nl/p/open-shading-language-for-blender.html
http://web.engr.oregonstate.edu/~mjb/prman/shaderfunctions.html
http://www.renderman.org/

http://www.csee.umbc.edu/~ebert/book/book.html