Parallelize TBB's adjacent_difference
Parallelize TBB's adjacent_difference

Fixes #184

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