requrements.txt incomplete, new api

[schmirgo]

requirements.txt does not contain readerwriterlock (unsure if needed)
requirements.txt does not contain rwlock

Fixes in utils.py and connection.py were necessary due to api changes in rwlock to get it running
Had to rename class reference/instantiation of ReadWriteLock to RWLock

[catborise]

RWLock comes with django but i do not know rwlock equals to djangos' RWLock.
no need to install rwlock with requirements because it is there already as file under vrtManager/rwlock.py