These are to canonicalize the offsets s.t if ```offset1 == offset2``` then ```offset1.name == offset2.name``` and `offset is offset2` for Pandas defined offsets. This does not currently hold:
```
In [10]: get_offset("QS-JAN") == get_offset("QS")
Out[10]: True

In [29]: get_offset("QS-JAN").name == get_offset("QS").name
Out[29]: False

n [31]: get_offset("QS-JAN") is get_offset("QS")
Out[31]: False
```

Adding these aliases fixes that.