Split VNC defines to vnc.h (Alexander Graf)

Split VNC defines to vnc.h (Alexander Graf)

The VNC protocol contains quite some constants, some of which are
currently hardcoded in the vnc.c code. This is not exactly pretty.

Let's move all those constants out to vnc.h, so they are clearly
separated. While at it, I also included other defines that will be
used later in this patch series.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6493 c046a42c-6fe2-441c-8c8c-71466251a162