Change namespace nsrs to ring_span_lite as used in ring_span.hpp

Use integral_constant and bool_constant supplied by ring_span.hpp

include/nonstd/ring.hpp

@@ -18,18 +18,10 @@
 # include <array>
 #endif
 
-namespace nonstd {
-
-namespace nsrs {
+namespace nonstd { namespace ring_span_lite {
 
 namespace std11 {
 
-template< class T, T v > struct integral_constant { enum { value = v }; };
-template< bool B       > struct bool_constant : integral_constant<bool, B>{};
-
-typedef bool_constant< true  > true_type;
-typedef bool_constant< false > false_type;
-
 template< class C >
 typename C::iterator begin( C & c ) { return c.begin(); }
 
@@ -358,7 +350,7 @@ class ring
 
 // Make types available in namespace nonstd:
 
-using nsrs::ring;
+using ring_span_lite::ring;
 
 } // namespace nonstd