A better python installation

[adler-j]

The current install script assumes the user wants to install for the python, and also happens to have a somewhat restrictive licence. When discussing this isuse in STIR with Kris he pointed out a better script, we should swap to that. Togeather with fixing issue #9, this would greatly improve the install process.

[kohr-h]

Part of the same issue, but going into a slightly different direction: We should have a setup.py for this package and should also implement a wheel build. That's the way to go in my opinion, hopefully it can be configured well enough so we can cover a couple of setups. Before I don't see a good chance to run CUDA tests on the CI machine.

[adler-j]

I see the point of setup.py, but why cant you simply cmake --FLAGS YOU NEED TO SET HARDCODED make for the CI?

[kohr-h]

Oh I don't mean for CI, but for distribution later. Of course, I can just set the flags as I need them for the CI machine.

[kohr-h]

I made some simple changes in the code, now it installs smoothly into a Py3 environment, too. And Jenkins can also build it now. You're going to get angry mails when you break something :-)