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).