work with new pip/tox
handle ResponseErrors when parsing MULTI in pipelines.

fixes #375
changelog
call socket.shutdown() before socket.close()
Merge branch 'lock_timeout' of git://github.com/vitek/redis-py into vitek-lock_timeout
changelog
version bump to 2.8.0
typo
Improved sentinel commands support
Add redis.sentinel module
Add docstrings for Sentinel class