- these mods improve socket performance under win32gdk.

 Before:
root [1] .x pserv.C
50000000 bytes received in 43.452999 seconds
 1.08 MB/s

After:
root [0] .x pserv.C
Receive 100 buffers of 500000 bytes over 5 parallel sockets...
50000000 bytes received in 1.532001 seconds
30.68 MB/s

Unfortunately TPServerSocket/TPSocket still have unscale behaviour
 under win32gdk.


git-svn-id: http://root.cern.ch/svn/root/trunk@8119 27541ba8-7e3a-0410-8455-c3a389f83636