[smuxi] Engine: use millisecond precision for storing last seen message and highlight (closes: #1064)

[Mirco M. M. Bauer <mmmbauer src gnome org>]

commit 5d192fe9f970a80ccfbd72522b10293d8d2be5f0
Author: Mirco Bauer <meebey meebey net>
Date:   Sun Jun 7 11:45:41 2015 +0200

    Engine: use millisecond precision for storing last seen message and highlight (closes: #1064)
    
    DateTime.ToString("u") only has second precision while Smuxi messages have
    sub-second precision. This caused that the last already seen Smuxi message was
    shown as unseen as the sub-second data got lost when it was stored in the SQLite
    database. ss.mmmm > ss.0 and thus it was newer/unseen.

 src/Engine/MessageBuffers/SqliteMessageBuffer.cs |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/Engine/MessageBuffers/SqliteMessageBuffer.cs 
b/src/Engine/MessageBuffers/SqliteMessageBuffer.cs
index f86db94..1f26cc4 100644
--- a/src/Engine/MessageBuffers/SqliteMessageBuffer.cs
+++ b/src/Engine/MessageBuffers/SqliteMessageBuffer.cs
@@ -76,7 +76,7 @@ namespace Smuxi.Engine
                     cmd.CommandText = sql;
                     var param = cmd.CreateParameter();
                     param.ParameterName = "timestamp";
-                    param.Value = value.ToString("u").Replace(" ", "T");
+                    param.Value = value.ToUniversalTime().ToString("o");
                     cmd.Parameters.Add(param);
                     cmd.ExecuteNonQuery();
                 }
@@ -109,7 +109,7 @@ namespace Smuxi.Engine
                     cmd.CommandText = sql;
                     var param = cmd.CreateParameter();
                     param.ParameterName = "timestamp";
-                    param.Value = value.ToString("u").Replace(" ", "T");
+                    param.Value = value.ToUniversalTime().ToString("o");
                     cmd.Parameters.Add(param);
                     cmd.ExecuteNonQuery();
                 }