Allow building of i386 FreeBSD box provisionerless or with Chef.
Use correct sudoers changes for Ubuntu 12+.

In the veewee definitions, Ubuntu 10 and 11 use the common ubuntu
configuration which exempts the admin group. The Ubuntu 12 and 13
definitions don't use the common configuration, instead they use the sudo
group.

Set exempt sudo user based on lsb_release and handle sudoers NOPASSWD
config change correctly.
For all Ubuntu boxes, use @jon918's unified sudoers script from [GH98] rather than random variants.
Merge branch 'jcd/use-jon918-sudoers'
Added Fedora 20 Beta support.
Migrate to RHEL 6.5. Also be consistent about the output package name.
Added new user variable: mirror
Modifed README.md how to use user mirror variable
Fixed debian-6.0.8-*.json to use mirror variable
Modified freebsd-9.1-i386.json to use mirror variable