Bug fixes or better error handling for the following 4 Windows bugs

Bug fixes or better error handling for the following 4 Windows bugs
(note, these changes haven't yet been tested on the PC which were
failing so no guarantee that they fully work):

a) GUI to cns improved so that you don't need a resize for the widgets to
   align properly, and so the interaction of typing: "username cr password
   cr" is all you need to do to get you a ticket.

b) cns uses krb5_us_gettimeofday instead of krb5_timeofday because the
   former is more accurate and handles timezones.  Probably should make
   the latter just call the former.

c) Added SOCKET_INIT and SOCKET_DESTROY around krb5_sendto_kdc to prevent
   some tcp/ip stacks from locking up after 8 uses.

d) Added a new error message and better error handling to give more
   precision as to why one PC was getting the error 'Cannot find KDC
   for requested realm.'

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@5342 dc483132-0cff-0310-8789-dd5450dbe970