gen_vcnet_vcproj.py

Create a few solution groups in the Visual C++ 2005 and 2008 solutions to
make it easier to find the module I'm working on.

This doesn't change the build, but groups the projects in the Visual Studio
IDE. The groups created are Libraries,
Libraries/Dlls, Libraries/Swig, Libraries/Java, Programs and Tests.

* build/generator/gen_vcnet_vcproj.py
(Generator.write): Calculate the group to place the project in and
provide the group to the ProjectItem constructor for usage by the
template writer.

* build/generator/vc2005_sln.ezt
(Template): Add 6 predefined group projects and add a group placement
block. This block declares in which parent a project should be shown.