Remove Visual Studio version-specific project and solution files
in favor of CMake.
CMake support for OpenEXR_Viewers
CMake support for PyIlmBase
Case-sensitive CMake module name fix.
Merge pull request #120 from openexr/vc_cleanup

Remove obsolete sln and vcproj files.  Extend CMake support to OpenEXR_Viewers and PyIlmBase.