Fix numeric serialization

src/Artemis.Core/JsonConverters/NumericJsonConverter.cs

@@ -0,0 +1,25 @@
+using System;
+using Newtonsoft.Json;
+
+namespace Artemis.Core.JsonConverters
+{
+    internal class NumericJsonConverter : JsonConverter<Numeric>
+    {
+        #region Overrides of JsonConverter<Numeric>
+
+        /// <inheritdoc />
+        public override void WriteJson(JsonWriter writer, Numeric value, JsonSerializer serializer)
+        {
+            float floatValue = value;
+            writer.WriteValue(floatValue);
+        }
+
+        /// <inheritdoc />
+        public override Numeric ReadJson(JsonReader reader, Type objectType, Numeric existingValue, bool hasExistingValue, JsonSerializer serializer)
+        {
+            return new Numeric(reader.Value);
+        }
+
+        #endregion
+    }
+}