offsets pickle issues
I'm overhauling `tseries.offsets` and finding a handful of workarounds that are in place "for prior pickles".  How important are these?  This process would be appreciably simpler if I could ignore those.

Related:

```
class MonthOffset(SingleConstructorOffset):
    _adjust_dst = True

    @property
    def name(self):
        if self.isAnchored:
            return self.rule_code
        else:
            return "%s-%s" % (self.rule_code, _int_to_month[self.n])
```

`isAnchored` is a method, not a property, so this is probably intended to be `if self.isAnchored()`.

