new style SIMD algorithms with polymorphic functions and pointers for transform and accumulate
move splat in accumulate, fix some typos and make transform return the output iterator
fixes in simd algorithms + test
add boost::simd::accumulate and boost::simd::transform that work on pointers and perform vectorization with prologues and epilogues. Unlike their std counterparts the function objects passed to these functions must be polymorphic and defined for both scalars and vectors