ZonedDateTime.Equals fails when using BCL-based zones

```
See http://stackoverflow.com/questions/26874303

Basically because we don't support comparing BCL-based time zones for equality, 
we don't support comparing ZDT values either, which really sucks.

It may be fixed for 2.0 already - I can't remember offhand what I've done about 
ZDT equality.
```

Original issue reported on code.google.com by `jonathan.skeet` on 12 Nov 2014 at 5:41
