Parameterized {jailbase,jaildir}
Replaced all usages of /usr/jail with $jaildir
Explicitly fail if $os isn't FreeBSD
Removed $__type/files/ as it is pointless to have now
Updated man page
Needed to use '|| true' on subshell variable assignments in case of empty return
Added default status (started=true or false)
Added default devfs rules
Replaced <<- HEREDOC usage with <<
Added escapes where necessary within quoted strings or HEREDOCs