Adds support for construction of (and use of) a new redhat_7 model type.
Includes changes to the underlying client configuration that allow for
changes to the timeout value used for POST operations (in the http_helper.rb
file) and adds a new script to the renamed 'scripts' directory that can be used
to create a 'minimized' version of RHEL ISOs (it has been tested under
RHEL7 and RHEL6 systems and on both we have successfully used this
script to minimize the size of rhel-6.5 and rhel-7.0 ISOs).
Model changes so that the operating systems deployed by Hanlon are all consistent...
with these changes in place, ruby and openssh-server are installed on each system
during the initial install (instead of doing it in the initial install for some models
and as a post-install proces in the rest).  Also removes addition of the PuppetLabs
repository and installation of Facter from the post-install scripts for some of these
models (and converts over from using Facter to get the IP address of the system during
the post-install to using standard UNIX/Linux utilities).
Merge pull request #196 from tjmcs/tb/add-rhel7-support

Adds support for construction of (and use of) a new redhat_7 model type.