Update setup.py

Having `description` in `setup.py` prevents project being listed as `UNKNOWN` on `pypi`
adapted features so it doesnt have lambdas for pickeling
added functions to save and load a classifier
active learning now it can take a classifier as parameter
adapted iepy runner to load and save classifiers
Merge branch '357-store-classifier' into develop
added --no-questions to the iepy runner
Merge branch '357-store-classifier' into develop
Applied patch by lowks. Thanks for the contribution!
document sentences now may return enriched tokens
views to navigate document
adapted template of document questions to be re-used on documents. added documents tempalte
added link on admin of documents
Merge branch '358-document-navigation' into develop
detecting instance out of date
download and unzip file, at once.
using unzip_from_url, and a bit of cleanup
paths bugfixing
safe mode import added
Moved all the instance-manipulation tasks to separated module, and implemented in there instance-upgrade