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
net.c v1.07 (Add support for IPv6--Host)

Add support for IPv6--Host.
Support for binding IPv6 address to host.
Add host_ipv6 flag.

Add host_ipv6 flag.
Default by 0.
Merge pull request #22 from wxue/master

net.c 1.07 | main.c 1.03 | net.h v 1.04 (Add support for both IPv4 and IPv6)