Turn whelk into a package, preparing to split the source
Split off tests, add more callback tests
Split off the subprocess subclasses

Whelk needs a modified subprocess, and needs to work on python 2.4+
For this we keep several versions of our subprocess modifications. Split
them off of the main code.
Relicense to zlib license
Update setup.py to the new structure, release 2.0
Merge branch 'master' into debian
New upstream version