Add simple std::set<> typemaps too

This is similar to the previous commit for std::map<>.

Lib/c/std_set.i

@@ -0,0 +1,48 @@
+/* -----------------------------------------------------------------------------
+ * std_set.i
+ *
+ * SWIG typesets for std::set
+ * ----------------------------------------------------------------------------- */
+
+%include <std_common.i>
+
+// ------------------------------------------------------------------------
+// std::set
+// ------------------------------------------------------------------------
+
+%{
+#include <set>
+#include <stdexcept>
+%}
+
+namespace std {
+  template<class T> class set {
+    public:
+      typedef size_t size_type;
+      typedef ptrdiff_t difference_type;
+      typedef T key_type;
+      typedef T value_type;
+      typedef value_type* pointer;
+      typedef const value_type* const_pointer;
+      typedef value_type& reference;
+      typedef const value_type& const_reference;
+
+      set();
+      set(const set& other);
+
+      size_t size() const;
+      bool empty() const;
+      void clear();
+      %extend {
+        bool add(const T& item) {
+          return self->insert(item).second;
+        }
+        bool del(const T& item) {
+          return self->erase(item) != 0;
+        }
+        bool has(const T& item) {
+          return self->count(item) != 0;
+        }
+      }
+  };
+}