Update requirements.txt

procname not on all systems, pysqllite 1.0.1 no longer available.
Update README.md

put in note about zfs
delineated first and second clientID to be a little more clear
Update requirements.txt
Update settings.py.sample
Update README.md

Add system requirements notes about OfflineIMAP and zfs
Merge pull request #1 from jkrauska/master

Minor tweak to requirements -- notes about install