Added capability for automatic updates (Ubuntu only)

It is necessary to add a remount to /tmp to enable exec permissions during
automatic updates
2.1-2.5 filesystem permissions

Add more restrictive permissions around the various file systems
including noexec, nosuid and nodev as appropriate
Moved /var/tmp management to 2_6, made the bind requirement (optional)

Using bind for /var/tmp is questionable because the retention semantics
of /tmp and /var/tmp are different, therefore we make this configurable
but defaulting to 'true' as specified by the CIS document