Fix emacsclient bug where "-n -c" does not open a new frame on Windows.

Fix emacsclient bug where "-n -c" does not open a new frame on Windows.

* lib-src/emacsclient.c (decode_options) [WINDOWSNT]: Don't force tty = 0;
instead, treat both -c and -t as always requesting a new "tty" frame,
and let server.el decide which kind is actually required.
Reported by Uwe Siart <usenet@siart.de> in this thread:
http://lists.gnu.org/archive/html/emacs-devel/2011-11/msg00303.html

* lisp/server.el (server-delete-client): On Windows, do not try to delete
the only terminal.
(server-process-filter): On Windows, treat requests for a tty frame as
if they were for a GUI frame if the running server is in GUI mode.