net.h v 1.04(add IPv6 support flag)

Add IPv6 support mark flag: IPv6
(set to 1 if support, otherwise set to 0)
main.c 1.03(ipcheck both ipv4 and ipv6)

Ipcheck() function can check both ipv4 and ipv6 validation since this
version.
net.c v1.07 (Add support for IPv6--Client)

Add support for IPv6--Client Info