CPackWIX: Handle multiple shortcuts in the start menu
CPackWIX: Add option to specify the language(s) of the installer

Add option "CPACK_WIX_CULTURES".
CMakeCPack: Provide an upgrade guid for WiX

Set CPACK_WIX_UPGRADE_GUID.  Without this upgrade GUID, you end up with
multiple instances of the same installation when installing cmake from a
WIX generated installer.
CPackWIX: Add support for custom WiX templates

WiX provides a lot of functionality for installers that cannot be
supported (easily) in the default WIX.template.in file.

For most users, the default template should be fine.  However if users
want to produce merge modules, include custom actions, etc, this new
option allows for a hook into how the wxs is produced.
SelectLibraryConfigurations: Use -NOTFOUND instead of copying the vars

If one of the libraries (_DEBUG or _RELEASE) is not set, the value is
set to the value of the other one.  FindQt4, from which the macro is
extracted, sets the values to XXX_LIBRARY_{DEBUG,RELEASE}-NOTFOUND
instead.  In both cases the XXX_LIBRARY is correct, but using NOTFOUND
makes it easier to understand which one is missing.

Update Tests/CMakeOnly/SelectLibraryConfigurations with the new logic.
Merge topic 'cpack-wix' into next

bf23891 CPackWIX: Add support for custom WiX templates
155bb01 CMakeCPack: Provide an upgrade guid for WiX
bfa2e29 CPackWIX: Add option to specify the language(s) of the installer
6e51ea9 CPackWIX: Handle multiple shortcuts in the start menu
Merge topic 'SelectLibraryConfigurations' into next

04d4dc3 SelectLibraryConfigurations: Use -NOTFOUND instead of copying the vars