Candidate instance is no longer aware of communities.

previously the candidate instance contained information on a per
community basis.  This meant that most methods contained an argument
to identify the community for which an event occurred.

We have changed the candidate to no longer be aware of communities.
This means that:

- all arguments specifying a community have been removed,
- some methods have been removed entirely (i.e. those that exclusively
  worked on all communities), and
- some methods have been rewritten to properties (i.e. those that no
  longer have any arguments).

All changes outside candidate.py reflect changes to handle these API
changes.
Prevent the endpoint from blocking.

UDP packets that are larger than 2^16 (including IP header) are
impossible to sent and will cause the endpoint to block.  When such a
thing occurs we will now raise a helpful exception.
Merge pull request #86 from boudewijn-tribler/endpoint

Prevent the endpoint from blocking.
Removed unused method.
Merge pull request #85 from boudewijn-tribler/candidate-cleanup

Candidate instance is no longer aware of communities.
Merge remote-tracking branch 'remotes/upstream/devel' into livebartercast

Conflicts:
	dispersy.py