Fixes #79 Add RHEL7 model

This pull request fixes issue #79.  The details are as follows:
Modified RHEL6 kickstart for RHEL7
Modified os_boot.erb for IP address for /etc/hosts and URL RHEL7 for facter
Modified http_helper.rb adding read_timeout for very large images like RHEL7
Modified client.rb adding new parameter http_read_timeout
```
[jcallen@virhanpaw001t Hanlon]$ cat cli/config/hanlon_client.conf 
--- !ruby/object:ProjectHanlon::Config::Client
noun: config
...
http_read_timeout: 300
```

The following test will show that the new http_read_timeout value works correctly:
```
time "/home/jcallen/rhel7/Hanlon/cli/hanlon" image add -t os -p /opt/hanlon/rhel-server-7.0-x86_64-dvd.iso -n rhel2 -v 7.1
Attempting to add, please wait...
Image Added:
 UUID =>  6AUAD9Z5QT6Xo3bk764rU
 Type =>  OS Install
 ISO Filename =>  rhel-server-7.0-x86_64-dvd.iso
 Path =>  /opt/hanlon/image/os/6AUAD9Z5QT6Xo3bk764rU
 Status =>  Valid
 OS Name =>  rhel2
 OS Version =>  7.1


real	2m54.773s
user	0m1.064s
sys	0m0.323s
```
[End result virtual machine](https://drive.google.com/file/d/0B5m8rApQhUzxZmFZUFFCMVhBR2s/edit?usp=sharing)