Packaging Improvements

In Developer installs (i.e., from `git clone`) running `make all` in `spinnaker_components` will copy the output binaries to `nengo_spinnaker/binaries`.  `setup.py` looks for binaries (`*.aplx`) in this location and will incorporate them into built `sdist`s.

Vertices will now look for their binaries in either the developer install environment, or in the system install environment.  In the case that the package was installed as an egg, and setuptools is installed, the binaries will be extracted on demand.  The function `vertices.resource_filename(pkg_name, filename)` is used to get a reference to the installed version of the given file.

As a user, given an `sdist` it is possible to run `python setup.py install` and have everything (including binaries) work.

The Simulator now accepts `machine_name` as a keyword argument, or will look for the machine name in the PACMAN config.

Some corrections and modifications to `setup.py`.