Added Shared project, resync'd net45 projects with dnx ones

src/Discord.Net.Shared/IdConvert.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Globalization;
+
+namespace Discord
+{
+    internal static class IdConvert
+	{
+		internal static readonly IFormatProvider _format = CultureInfo.InvariantCulture;
+		
+		public static long ToLong(string value)
+			=> long.Parse(value, NumberStyles.None, _format);
+		public static long? ToNullableLong(string value)
+			=> value == null ? (long?)null : long.Parse(value, NumberStyles.None, _format);
+		
+		public static string ToString(long value)
+			=> value.ToString(_format);
+		public static string ToString(long? value)
+			=> value?.ToString(_format);
+	}
+}