Update header files to use a more standard name to prevent rereading

This is from github report #16. There are likely a few more issues
that need to be addressed though this takes care of the major ones.

vhdlpp/scope.h

@@ -1,7 +1,7 @@
-#ifndef __scope_H
-#define __scope_H
+#ifndef IVL_scope_H
+#define IVL_scope_H
 /*
- * Copyright (c) 2011-2013 Stephen Williams ([email protected])
+ * Copyright (c) 2011-2014 Stephen Williams ([email protected])
  * Copyright CERN 2013 / Stephen Williams ([email protected])
  *
  *    This source code is free software; you can redistribute it
@@ -226,4 +226,4 @@ class ActiveScope : public ScopeBase {
       Entity*context_entity_;
 };
 
-#endif
+#endif /* IVL_scope_H */