Improve the vtkChartXY example.

- show the legend
- show the sine function
- colorized plots

	modified:   src/vtk/vtk_example_01.cxx
Update the CMake script of the VTK examples.

It tries the create an executable for each C++ source file following,
this globbing expression:
	vtk_example_*.cxx
as 'vtk_example_01.cxx'

	modified:   src/vtk/CMakeLists.txt