Clang fixes

-Wshadow in MR.c, size was already used
CM.c: pointer arithmetic on void* is a GNU extension
SendData.h: add extern for -Wmissing-variable-declarations
AB.h: add missing enumerations
readtag.c: eliminate unnecessary debug output

Only read twice in Connect() if writing
tuxeip: fixes for winsock2

MSVC needs io.h for close() in Ethernet_IP.c
Add WSACleanup() calls after close()'s for win32
Must call WSAStartup() before using a socket under winsock
Version 2.2 was released in 1997, safe to assume we can use it instead.