Merge branch 'bugfix/TrackedRecord-IsDirty' into release/5.1.0

Fixed a bug where a calling `SetValue()` with the same value that an existing record was set to would mark the record as `IsDirty`. Only changes in `Value` should result in `IsDirty`. This seems to stem from an issue with the `==` operator on `T` not using the `==` from `String`, even when `T` is of type `String`. This is an unexpected scenario, and will require further investigation. In the meanwhile, using `Equals()` solves #86.

Author: JeremyCaney

OnTopic/Collections/Specialized/TrackedRecordCollection{TItem,TValue,TAttribute}.cs

@@ -458,7 +458,7 @@ internal void SetValue(
         else if (markDirty.HasValue) {
           markAsDirty = markDirty.Value;
         }
-        else if (originalItem.Value != value) {
+        else if (!originalItem.Value?.Equals(value)?? false) {
           markAsDirty = true;
         }
         else if (!version.HasValue) {