Implement fix suggested by magnum
More fmt_main name convention fixes
Change the plugin magic in Makefile so formats are loaded in alphabetic
order of format struct names. Also, change the struct for raw-sha512 so
it will take precedence over other 64 byte (128 hex chars) bare hash
formats (currently raw blake2).
Change name of blake2-512 to raw-blake2-512, so it doesn't get bullied
by the rest of the raw format gang.