Fix #45 and #47

This should fix #45 and #47.

The latter appears to be a bug in the PyPy version on Traivs (PyPy 2.2.1 with GCC 4.6.3) which seems to have been addressed in a later version. I could not reproduce the error with PyPy 2.3.0-alpha0 running locally. The alternative solution in the pull request is not as elegant as ``collections.namedtuple``, but it would help us move on without having to wait for the next stable release of PyPy.

In addition to the above two, I've
* fixed a naming conflict issue between ``immutable.list.Deque`` and ``immutable.finger.Deque``, and
* added Python 3.4 to the Traivs config