Consolidate usage of VsProjectType

Move ProjectFileExtension handling logic to use ProjectType and remove
extraneous checks in .Net SDK style project generation. This change will
make introducing new project types relatively simpler.

Source/cmLocalVisualStudioGenerator.h

@@ -10,6 +10,7 @@
 
 #include "cmGlobalVisualStudioGenerator.h"
 #include "cmLocalGenerator.h"
+#include "cmVsProjectType.h"
 
 class cmCustomCommand;
 class cmCustomCommandGenerator;
@@ -30,15 +31,9 @@ public:
   cmLocalVisualStudioGenerator(cmGlobalGenerator* gg, cmMakefile* mf);
   virtual ~cmLocalVisualStudioGenerator();
 
-  /** Construct a script from the given list of command lines.  */
-  enum class IsCSharp
-  {
-    No,
-    Yes
-  };
   std::string ConstructScript(cmCustomCommandGenerator const& ccg,
                               const std::string& newline = "\n");
-  std::string FinishConstructScript(IsCSharp isCSharp,
+  std::string FinishConstructScript(VsProjectType projectType,
                                     const std::string& newline = "\n");
 
   /** Label to which to jump in a batch file after a failed step in a