Allow the examples to specify what modules to use.

This approach demonstrates good programming practice by only
linking to the needed modules.
It also removed the need to set CMP0020 to NEW in all cases
except those examples that link to Qt.

The include(${VTK_USE_FILE}) has been removed from the
top-level CMakeLists.txt file as it is unnecessary.

The solution presented here will work with the Examples built
as a stand-alone folder or within the VTK tree or with the
individual examples.

They have been tested on Linux, Windows VS2012 Express,
Mac OS-X 10.9 using Qt5.1.1.

Change-Id: I0572a395b2ebc6630db8c1407f410a584f668a85
Signed-off-by: Andrew Maclean <andrew.amaclean@gmail.com>
Merge topic 'make-vtk-examples-build' into master

733ef2dd Allow the examples to specify what modules to use.