Fix price cache. Add OSVersion to PIng controller

MarketData/MarketDataLib/Cache/LocalPriceCache.cs

@@ -73,6 +73,10 @@ namespace MarketData.Cache
     {
       lock(typeof(LocalPriceCache))
       {
+        if(Utility.IsEpoch(latestDate))
+        {
+          RefreshLatestDate();
+        }
         return latestDate;
       }
     }

MarketDataServer/Controllers/PingController.cs

@@ -15,5 +15,12 @@ namespace MarketDataServer.Controllers
       MDTrace.WriteLine(LogLevel.DEBUG,String.Format("[{0:G}][PingController::GetPing]", DateTime.Now));
       return true;
     }
+
+    [HttpGet(Name = "GetSystemInfo")]
+    public String GetSystemInfo()
+    {
+      MDTrace.WriteLine(LogLevel.DEBUG,String.Format("[{0:G}][PingController::GetSystemInfo]", DateTime.Now));
+      return Environment.VersionString.;
+    }    
   }
 }