Lipu Fei

Got another one in tracker log: ``` Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 402, in startReactor self.config, oldstdout, oldstderr, self.profiler, reactor) File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 323, in runReactorWithLogging reactor.run()...

@NielsZeilemaker I have a branch on Tribler that changes some database to use an ORM called [Axiom](https://divmod.readthedocs.org/en/latest/products/axiom/axiom-why-axiom.html). I converted all tables expect the Channel-related ones to use Axiom and it...

https://github.com/LipuFei/tribler/tree/refactory_axiom_db

@whirm I'll remove the pep8 commit for now, otherwise the PR is too difficult to review.

@NielsZeilemaker I made this PR to make it easy for us to review. Thanks! I'll check everything again.

@NielsZeilemaker What does the `permission_triplets` mean?

@NielsZeilemaker I had thought about it and I decided to duplicate the undo stuff instead of messing them up. Later, when we want to remove the undo, we can simply...

@whirm I guess this is more or less it. I will check the unit tests one more time after my presentation rehearsal. Also, before we merge, we should change the...

@NielsZeilemaker One of the cancel message tests didn't pass. The test does the following: ``` Three nodes: SELF, NODE, OTHER What they do: 1. SELF gives NODE the permission to...

@NielsZeilemaker I've made a wiki page: https://github.com/Tribler/dispersy/wiki/Cancel-Message. Hope it explains.