Revert "Remove unused objects file"

This reverts commit b8739a2cc0114cb473ed249f8f58828b4c12d803. The objects file
is actually still imported by various modules. I didn't test if these modules
actually need this import, though. However, this revert is a quick fix for
allowing me to set up a new CATMAID instance.

In general, when removing a module from the repository, one needs to make sure
that also the compiled python module (pyc file) gets removed. Otherwise one
would not see errors which might be caused by this removal.