Fixes Bug 996029 - added temporary file system class that recycles directories

this is the second PR for this effort, the first suffered from some git complications where a bunch of unrelated commits were tagging along and wouldn't let go.    

here are three classes out of this effort:

```FSTemporaryStorage``` - the directories recycle on a monthly basis with roots in the form 'DD', can be traversed in an FIFO order using the 'new_crashes' method.  Useful as temporary storage between the collector and the crashmover.
 
```FSDatedPermanentStorage``` - the directories work as they do now with roots in the form 'YYYYMMDD' and can be traversed in a FIFO order using the 'new_crashes' method.  This is friendlier named alias for the current filesystem storage called ```FSLegacyDatedRadixTreeStorage```.  Kept for legacy use only by us, may be useful to other installations.

```FSPermanentStorage``` - the directories work as they do now with roots in the form 'YYYYMMDD' minus the ability to do a FIFO traversal.  This storage method is useful for installations that want only file system storage system rather than using HBase.  This is a friendlier alias for the existing ```FSLegacyRadixTreeStorage```