fix overflow when a table is its own metatable. References #4

spec/inspect_spec.lua

@@ -191,6 +191,15 @@ describe( 'inspect', function()
   }
 }]])
       end)
+
+      it('accepts a table that is its own metatable without stack overflowing', function()
+        local x = {}
+        setmetatable(x,x)
+        assert.equals(inspect(x), [[<1>{
+  <metatable> = <table 1>
+}]])
+      end)
+
     end)
   end)
 end)