Only export to eds variables with the [EdsExport] attribute fixes #52

EdsExport was not being tested during save and was wrong on one
variable. Fixing this also removed 4 special cases that were excluded on
export

libEDSsharp/eds.cs

@@ -213,13 +213,8 @@ public void write(StreamWriter writer)
 
             foreach (FieldInfo f in fields)
             {
-                if (f.Name == "EDSVersionMajor")
-                    continue;                 
-                if (f.Name == "EDSVersionMinor")
-                    continue;
-                if (f.Name == "CreationDateTime")
-                    continue;
-                if (f.Name == "ModificationDateTime")
+
+                if (!Attribute.IsDefined(f, typeof(EdsExport)))
                     continue;
 
                 if (f.GetValue(this) == null)
@@ -462,9 +457,9 @@ public class FileInfo : InfoSection
         [EdsExport]
         public byte FileRevision;//=1
 
-        [EdsExport]
+
         public byte EDSVersionMajor;//=4.0
-        [EdsExport]
+
         public byte EDSVersionMinor;//=4.0
         [EdsExport]
         public string EDSVersion="";