Deleting pcc objects causes exceptions on server side

[arthur00]

The NodeSimulation added to the last commit works, but is constantly causing KeyError exceptions on the server side. Below is an example output.

  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/flask/views.py", line 84, in view
    return self.dispatch_request(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/flask_restful/__init__.py", line 587, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store_server.py", line 52, in wrapped
    ret = f(*args, **kwds)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store_server.py", line 147, in post
    FrameServer.Store.put_update(sim, typeObj, new, mod, deleted)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store.py", line 240, in put_update
    return self.__put_update(app, tp, new, mod, deleted)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store.py", line 275, in __put_update
    self.__base_store.delete(tp, id)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store.py", line 70, in delete
    del self.__data[tp][id]
KeyError: u'8606efe2-ec19-4c0d-b379-7ef9237a1d68'
[root] Exception handling function post:
Traceback (most recent call last):
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store_server.py", line 52, in wrapped
    ret = f(*args, **kwds)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store_server.py", line 147, in post
    FrameServer.Store.put_update(sim, typeObj, new, mod, deleted)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store.py", line 240, in put_update
    return self.__put_update(app, tp, new, mod, deleted)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store.py", line 275, in __put_update
    self.__base_store.delete(tp, id)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store.py", line 70, in delete
    del self.__data[tp][id]
KeyError: u'8606efe2-ec19-4c0d-b379-7ef9237a1d68'
[spacetime.store_server] Exception on /NodeSimulation/RouteRequest [POST]
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/flask_restful/__init__.py", line 477, in wrapper
    resp = resource(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/flask/views.py", line 84, in view
    return self.dispatch_request(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/flask_restful/__init__.py", line 587, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store_server.py", line 52, in wrapped
    ret = f(*args, **kwds)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store_server.py", line 147, in post
    FrameServer.Store.put_update(sim, typeObj, new, mod, deleted)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store.py", line 240, in put_update
    return self.__put_update(app, tp, new, mod, deleted)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store.py", line 275, in __put_update
    self.__base_store.delete(tp, id)
  File "/Users/arthurvaladares/Dropbox/workspace/spacetime/python/spacetime/store.py", line 70, in delete
    del self.__data[tp][id]
KeyError: u'8606efe2-ec19-4c0d-b379-7ef9237a1d68'