Update item.py

fixed Item.getChildren bug (see https://github.com/fcheslack/libZotero/issues/11)
Update items.py

fixed Item.getChildren bug (see https://github.com/fcheslack/libZotero/issues/11)
Merge pull request #14 from paregorios/master

python: fetching export formats, respect backoff, customize user-agent header
Merge pull request #12 from fruehwir/master

Fix for item.getChildren issue closes #11
add debug printout of response headers
Merge branch 'master' of github.com:paregorios/libZotero

getting everything up to date