[boost] [patch] Patch for eliminating some warnings

Hi, During testing for phoenix i came over some warnings which were fairly easy to fix. The warnings showed up by compiling with -Wall -Wextra -ansi -pedantic on gcc and clang. They are mostly about unused parameters or extra semicolons. The affected files are: hing file boost/fusion/algorithm/iteration/detail/fold.hpp boost/fusion/sequence/intrinsic/has_key.hpp boost/fusion/view/ext_/segmented_iterator.hpp boost/function/function_template.hpp boost/regex/pending/unicode_iterator.hpp Patch is attached. Safe to apply? Greetings, Thomas