Added man page plugin command warning

As of now, the man page does not update when plugins are installed.
Updated man page date

I forgot to change it. I even left myself a reminder!
Make help output more consistent
Use -qq flag on apt-get to quiet installations of packages
Silence curl stderr progress output
Ensure curl is installed before using command
Fix issue where certain hosts will not have add-apt-repository installed due to missing packages
Simplify the vagrant workflow

- Moved from wget to cloning the repository
- Add acl-add command to Make
- Modify the docs to use the new methodology
Add a passthru make target for running dokku commands within the vagrant vm
Change targets to vagrant-*
Merge pull request #708 from progrium/576-fix-vagrant

576 fix vagrant
Merge pull request #698 from tombell/clean-up-help

Make `help` command output more consistent
Explicitly install man-db

Dokku requires mandb, but the man-db package is not part of the
minimal Ubuntu base - so install it.
Merge branch 'install_man-db'
Restart app only if config changed
Merge branch 'check-config-changes'
Fixed port removal when docker is start with --ip with an IP other than 0.0.0.0
Merge branch 'fix-port-ip'
Fixed variable name.

RESTART_APP was initialized as RESTART.
Merge branch 'fix-variable-name'