added permutation_iterator example
added permutation_iterator example

--HG--
extra : convert_revision : svn%3A83215879-3e5a-4751-8c9d-778f44bb06a5/trunk%40864

raygit/thrust,mohamed-ali/thrust,GrimDerp/thrust,arnabgho/thrust,sdalton1/thrust,dachziegel/thrust,xiongzhanblake/thrust_src,arnabgho/thrust,Ricardo666666/thrust,sarvex/thrust,GrimDerp/thrust,zhenglaizhang/thrust,Ricardo666666/thrust,xiongzhanblake/thrust_src,xiongzhanblake/thrust,thrust/thrust,xiongzhanblake/thrust_src,egaburov/thrust,thrust/thrust,jaredhoberock/thrust,dachziegel/thrust,zhenglaizhang/thrust,mohamed-ali/thrust,andrewcorrigan/thrust-multi-permutation-iterator,zeryx/thrust,raygit/thrust,sarvex/thrust,mohamed-ali/thrust,andrewcorrigan/thrust-multi-permutation-iterator,jaredhoberock/thrust,thvasilo/thrust,marksantos/thrust,thvasilo/thrust,zeryx/thrust,egaburov/thrust,egaburov/thrust,jaredhoberock/thrust,xiongzhanblake/thrust,raygit/thrust,sdalton1/thrust,sarvex/thrust,andrewcorrigan/thrust-multi-permutation-iterator,arnabgho/thrust,thrust/thrust,sdalton1/thrust,dachziegel/thrust,GrimDerp/thrust,zeryx/thrust,marksantos/thrust,thvasilo/thrust,xiongzhanblake/thrust,thrust/thrust,jaredhoberock/thrust,zhenglaizhang/thrust,marksantos/thrust,thrust/thrust,jaredhoberock/thrust,Ricardo666666/thrust