Feature pithoschanges

Includes the necessary changes for better integration with Pithos

Noticeable changes:

* Add signature for v2 maps
* Add v0 map hint
* Support map creation from a given object list
* Remove "archip_" prefix from maps and blocks created by archipelago
* Add rename functionality
* Immediately delete writeable objects when removing a map
* Add readonly option when mapping a volume
It can. Pair is actual one of the following:
pid=4362
minor=0
state=0
args=archipelago:volname:mport=1001:vport=500:assume_v0:v0_size=1245

So when we split with the '=' char, the key is always the first element and the rest is the value. This is needed for the args param, where the key is args and the value is archipelago:volname:mport=1001:vport=500:assume_v0:v0_size=1245

So I believe the code is handling it correctly