FFOS v1.7

+ ffaio_sendv()
+ ffiov_shiftv()
+ ffrnd_* - random numbers
+ BSD: support new accept4() on FreeBSD 10
* BSD: now ffskt_sendfile() doesn't send the whole file if 'file-size' parameter is 0
* ffaio_cancelasync() cancels the specified operation only
* fferr_str(), ffaddr_info() work with char* now
* windows: fixed gcc compiler warnings