Feature Request: Calendar API support

```
This API is in the works : https://github.com/CallMeFoxie/Calendar

Requesting JAS support Calendar API with tags of some sort, to allow for control of mob spawning per season.

Usage examples:
 Ducks != Winter
 Bears != Winter
 Bees = Summer
 Groundhogs = Spring ;-)
```

https://github.com/ProjectZulu/Project-Zulu/issues/104
