Update examples for multi-target compilation.

Makefile and vcxproj file updates.
Also modified vcxproj files so that the various files ispc generates go into $(TargetDir),
  not the current directory.
Modified the ray tracer example to not have uniform short-vector types in its app-visible
  datatypes (these are laid out differently on SSE vs AVX); there was an existing lurking
  bug in the way this was done before.

examples/deferred/kernels.ispc

@@ -66,8 +66,6 @@ struct InputHeader
     uniform int32 inputDataArrayOffsets[idaNum];
 };
 
-export void foo(reference InputHeader h) { }
-
 
 ///////////////////////////////////////////////////////////////////////////
 // Common utility routines