Use Ruby's to_s for floats

This matches JSON's behaviour exactly. I'll look at ways to regain the
speed later.

Author: jhawthorn

ext/rapidjson/encoder.hh

@@ -122,19 +122,12 @@ class RubyObjectEncoder {
                 }
             }
         } else {
-            // HACK: for standard notation we can use the RapidJSON
-            // implementation, but for values we need scientific notation we
-            // will fallback to Ruby's to_s so that we match JSON's output
-            // exactly.
-            //
-            // Ideally we would just implement both
-            if (f <= -1.0e15 || f >= 1.0e15 || (f >= -0.0001 && f <= 0.0001)) {
-                VALUE str = rb_funcall(v, rb_intern("to_s"), 0);
-                Check_Type(str, T_STRING);
-                encode_raw_json_str(str);
-            } else {
-                writer.Double(f);
-            }
+            // TODO: We should avoid relying on to_s and do this conversion
+            // ourselves. However it's difficult to get the exact same rounding
+            // and truncation that Ruby uses.
+            VALUE str = rb_funcall(v, rb_intern("to_s"), 0);
+            Check_Type(str, T_STRING);
+            encode_raw_json_str(str);
         }
     }