Sync changes from IceCube svn

It would be good to cook this down to one repository. Between the old local repo in Zeuthen, the version in IceCube svn, and the one on GitHub, it's hard to point potential users to the correct canonical location. To that end, I propose the changes in this PR, plus the following steps:

- Make the version in IceCube svn raise an error when it's imported, and point to the GitHub version
- Put the docs on readthedocs.org
- (optional) Register with PyPI