FF v1.8

+ ffsf: send file with headers and trailers
+ ffpath_isvalidfn()
+ ffuri_scheme2port()
+ ffaddr_set()
+ ffmemcpy(), ffmem_copy() macros
* ffrbtl: sibling list is cycled now
+ FFRBT_ENUMSAFE()
- ffbuf_add() now always sets dst->len