Revert "Deleted entry from urls.py, as view has been removed."

This reverts commit 7d65944f1857e6b3423f24374f3e3f20abeadb9c.
Revert "Annotator now gets sentences from nested API."

This reverts commit 6e4ba094e5f589c4cea352ab3df4a7e4efe2fa5a.
Revert "Reworked annotator urls to always include project, cleaned code a little bit."

This reverts commit 189f9632f451f58177a88c62172fa33fe2758443.
codebook empty string -> none
Merge branch 'master' of github.com:amcat/amcat
Add python-memcached as pip-requirement