Workspace management

>>> from woger import WorkspaceManager, BasePathStructure
>>> import tempfile
>>>
>>> class PathStructure(BasePathStructure):
...     loaded = 'loaded.xml'
...     parsed = 'parsed.json'
>>>
>>> manager = WorkspaceManager('store', PathStructure)
>>>
>>> manager.create(1346)
<Workspace(store/1346)>
>>>
>>> manager.create(542)
<Workspace(store/542)>
>>>
>>> manager.target_latest()
>>> manager.target()
<Workspace(store/1346)>
>>>
>>> manager.current() is None
True
>>>
>>> manager.update()
>>> manager.current() is manager.target()
True