Fixed inet_pton and a new Winsock UDP bug.

inet_pton was copying the entire sockaddr_in struct,
rather than just the sin_addr field...

I am a bit unsure about the UDP fix, because it may affect
TCP as well. On UDP sockets, when a sendto fails, the next
receive/receivefrom fails with CONNRESET. I changed
sock_recv/sock_recvfrom in wsocket.c to skip the CONNRESET
from the recv/recvfrom, hoping that if the socket is TCP,
sock_waitfd will get the CONNRESET again. The tests pass,
but this should be tested more thoroughly.