Double to str conversion fix

Forced en-US locale when converting double to string to ensure that .
(dot) is used as delimiter. InfluxDB won't accept anything else than dot
regardless on current locale.

Author: SPM

AdysTech.InfluxDB.Client.Net/InfluxDBClient.cs

@@ -254,7 +254,7 @@ public async Task<bool> PostValueAsync(string dbName, string measurement, long t
                     new KeyValuePair<string, string>("precision", precisionLiterals[(int) precision])
                     }).ReadAsStringAsync ();
 
-            var content = String.Format ("{0},{1} {2}={3} {4}", measurement, tags, field, value, timestamp);
+            var content = String.Format (System.Globalization.CultureInfo.GetCultureInfo("en-US"), "{0},{1} {2}={3} {4}", measurement, tags, field, value, timestamp);
             ByteArrayContent requestContent = new ByteArrayContent (Encoding.UTF8.GetBytes (content));
             HttpResponseMessage response = await PostAsync (builder, requestContent);
 
@@ -295,7 +295,7 @@ public async Task<bool> PostValuesAsync(string dbName, string measurement, long
             //    content.AppendFormat ("{0},{1} {2} {3}\n", measurement, tags, value, timestamp);
             ////remove last \n
             //content.Remove (content.Length - 1, 1);
-            var valuesTxt=String.Join (",", values.Select (v => String.Format ("{0}={1}", v.Key, v.Value)));
+            var valuesTxt=String.Join (",", values.Select (v => String.Format (System.Globalization.CultureInfo.GetCultureInfo("en-US"), "{0}={1}", v.Key, v.Value)));
             var content = String.Format ("{0},{1} {2} {3}", measurement, tags, valuesTxt, timestamp);
 
             ByteArrayContent requestContent = new ByteArrayContent (Encoding.UTF8.GetBytes (content.ToString ()));