Imported libpng sources, because they are required for static linking.
Adapted imported libpng for VC2008 project files.

The modules gltestdll and surface.vcproj don't really
depend on libpng directly, but these projects' include paths
are fixed, too.
Moved surface module's VC2008 project file into a subdirectory.

This is for preparing to convert to VC2012 in a consistent way as
the gltestdll module's.
Adapted libpng for VC2012 project files.
Imported jpeg-9 library for Windows.
Added IJG JPEG library's VC2012 project to the solution.

The jconfig.h configuration file is copied from jconfig.vc in the
pre-build hook of VC2012's project file, in order to make it portable
among other implementations.
Added VC2008 project file for jpeg static library.

Also added ignore pattern for jconfig.h.