index doc tweaks
more doc tweaks, be explicit about server host/port in basic example
more doc tweaks
factor out common bits from both queues
re-use client.ensure_path method
rename `Queue._ensure_parents` to `_ensure_paths`
move _ensure_paths call in `__len__` into base class
factor out `_ensure_paths` into queue base class
use transaction as a context manager
more queue api docs tweaks