Upgrading installation to setuptools

[Dapid]

This should close #3, and along the way, also #2.

I am having some trouble linking to Eigen in my box, here is the log: https://gist.github.com/Dapid/94cff5f6f3b4124a23da

The problem seems to be lu.

[Dapid]

Travis is using an older Cython that doesn't support explicit relative imports. Upgrading it and retriggering.

[Dapid]

Finally it works! I have bundled a bunch of things in this PR, but it was needed to make it work.

Travis is using Eigen 3.0.5, but the installation fails on Fedora with Eigen 3.2.5, as the log shows. I will go through the release notes and see if there has been any change.

[strohel]

Thanks for this pul request, I'll look at the commits more closely as soon as I find some time.

One thing to note now, however: would you mind changing the commit messages to be in simple (not continuous) present tense? i.e. "migrate to setuptools" instead of "migrating to setuptools". This is what git developers themselves use, see https://git.kernel.org/cgit/git/git.git/tree/Documentation/SubmittingPatches?id=HEAD

Also, I would prefer if you squash the commit fixups, i.e. hide the sausage-making. (see also https://sethrobertson.github.io/GitBestPractices/#sausage )

[Dapid]

I have squashed it into three logical commits, that I think will make it easiest to review. All tests pass locally and on Travis.

[strohel]

Thanks, @Dapid - sorry for being extremely slow to respond, I've been rather busy lately, you know that.. I'll have a look at the latest version when time permits.

[Dapid]

Don't worry, I understand. Better to get this right.