Added reference docs for hgfs.
Make the publisher high water mark configurable
Fix LOGS_DIR path - 'ROOT_DIR/var/log/salt', not 'ROOT_DIR/var/logs/salt'
Merge pull request #6910 from dlanderson/fix_syspath

Fix LOGS_DIR path - 'ROOT_DIR/var/log/salt', not 'ROOT_DIR/var/logs/salt...
Merge pull request #6909 from shadowfax-chc/hgfs-docs

Added reference docs for hgfs.
doh!