William Steig, whose drawings and cartoons appeared in the New Yorker for six decades, died last Friday in Boston at the age of 95.  Steig got his first cartoon published in the New Yorker in 1930 and eventually placed more than 1,600 drawings in the magazine for which he also contributed 117 covers.  In the 1970s Steig began writing children's books, almost all of which are still in print.  Steig's secret was that he never talked down to kids.  Instead he used a challenging and sonorous vocabulary made understandable by his superb drawings.  The most famous of Steig's children's books today is probably Shrek, which was made into a hugely popular film by Jeffery Katzenberg and the animators at Dreamworks, who used Steig's subversive story to rip the Disney approach to fairy tales to shreds.  Steig also revolutionized the greeting cards industry in the 1930s by introducing heavy doses of sarcasm and black humor into what had been a domain ruled by affable pleasantries.