Using numpy.distutils for the setup.py + f2py for obspy.taup

I moved obspy.taup from ctypes to f2py. This should get rid of quite a lot of compilation problems related to obspy.taup.

In the course of the transition I also converted the existing setup.py to numpy.distutils. This results a sizable reduction of the amount of source code and the complexity of the setup.py as almost all hacks mainly related to Fortran are no longer necessary. Furthermore the custom extension class has been removed from the setup.py script.

It is currently tested only on Linux so some more changes might be necessary to successfully run it on Windows and OSX.

One small issue remains: One temporary file needs to be created in the course of the setup. This is necessary to be able to have architecture specific library filenames. The natural place to put the temporary file would be the `build/` subdirectory. This works fine as long as it is installed from source. Installing it via `pypi` or other means, results in a different build directory. I could not find a reliable way to get the path of the build directory within the setup.py. As a consequence, currently a `build/` folder is created in the current working directory.