Remote manager operations

[anaion]

This is a work in progress implementation to add support for the managers to spawn agents without accessing the libcloud interface, but using the director. The API for handling requests on the server's side contains now only the functions for creating and deleting a node (this is where the interface for the nested cloud will be integrated).

There are still many harcoded configuration settings (urls, paths). If you want to test, please grep for TODOs in the committed files.

[gtato]

Could any of you guys re-explain me what was the problem with reservation timers?

Some comments:
I statically reviewed ee959cd and I think it is generally okay. However it requires a bit or reorganization while merging it. For example I think the ProxyController should be merged with Controller because currently it is just a wrapper around it. Additionally the nestedapi methods should be added to the director page (maybe the service.py) while AgentController can go together with ManagerController in cloud.py.

Generally I think that the impact of merging this part of code is quite small however I also think that quite some testing is required. I have got the impression that everyone is quite busy and there are still other issues to fix. For this reason I would give it a high priority to the integration of this part right after the release but not before.