Revert "still didn't get the permissions right, chmod must follow sa-learn's initial creation of files"

This reverts commit 495790d81da72c2ac9ca70c31b47c7ae7063df81.
Revert "clean up setup/spamassassin.sh"

This reverts commit dfe0a9f1872dc048ad64301be4c8795bc713dd92.
Revert "give dovecot antispam plugin's sa-learn-pipe script permission to write to the bayes files"

This reverts commit 7ca54a2bfb12179ffbd8d0c00f44efee7d0e5a4e.
Revert "Change owner of spamassassin directory from mail to spampd, closes #231"

This reverts commit b26abc947e8d39d457f6ce098544aa1692de9a56.
Disable learning within spampd, add back documentation improvements
Merge branch 'spamassassin-simplification' into develop