Clean up GnuTLS linking and instructions

GnuTLS can have different crypto backends, and it is rarely gcrypt
these days. So we should not be including that unconditionally,
and should not be pointing people at it either. Also remove the
section about Win32 binaries as those are out of date and probably
insecure. Lastly remove the section about static builds as it is
a general issue and in no way complete with just the GnuTLS portions.
Remove libjpeg-turbo build instructions

There is nothing special about this library that warrants special
treatment.
Link basic X11 libraries last

The extension libraries might depend on libXext or libX11, so
make sure they come last on the link line.
Move ws2_32 dependency to the correct place

It is rdr and network that needs it, not vncviewer.
Add Carbon and Cocoa dependencies to vncviewer

We use both frameworks directly from vncviewer so we should
make sure they get pulled in.
Extend "static" build option

Try to link as much as possible statically in an effort to produce
binaries that can be run everywhere.
Merge branch 'build' of https://github.com/CendioOssman/tigervnc