Added local optimization -((a - b) + c) -> (b - a) - c.
cleanup, use C99
use designated initializers for arch_isa_if structs
use designated initializers for arch_env
use designated initializers for backend_params
make most of irarch API private

This removes functions from the public API which are pointless outside
localopt rules, and also avoids another struct in the public API.
normalize util.h includes
remove unused k_ir_op
remove k_ir_prog
remove a bunch of is_XXX firm_kind convenience functions

This sort of typeless programming is bad style and deprecated.
cleanup, use C99
cleanup, use C99
update amd64 TODO
cleanup
cleanup
cleanup, use C99
cleanup, use C99
cleanup, use C99