Provide a comparator to capture a value for later inspection

```
Mox should provide a comparator to capture a value for later inspection, like 
EasyMock's Capture.  The Remember comparator can almost do this, but the value 
attribute is non-public.
```

Original issue reported on code.google.com by `mattmccu...@google.com` on 16 Aug 2012 at 8:26
