Make package version configurable

Make the horizon package configurable.
Also provide a static name for the horizon package resource.
Redirect / to /dashboard on RedHat
Re-introduce enabling mod_wsgi after fbe4fbc
Merge pull request #38 from bodepd/allow_package_ensure_config

Make package version configurable
Merge pull request #41 from Mirantis/redirect-to-dashboard-on-redhat

Redirect / to /dashboard on RedHat
Merge pull request #39 from Mirantis/reintroduce-enabling-mod-wsgi

Re-introduce enabling mod_wsgi after fbe4fbc
Depend on memcached if it is defined, not if it is on 127.0.0.1

Important in case memcached is local but binds to an address other than 127.0.0.1.
Include apache
Added logging for horizon
Merge pull request #40 from Mirantis/include-apache

Include apache
Merge pull request #42 from Mirantis/logging

Added logging for horizon
Merge pull request #44 from Mirantis/require-memcached-if-defined

Depend on memcached if it is defined, not if it is on 127.0.0.1
Bind address is configurable
Merge pull request #45 from Mirantis/bind-address-configurable

Bind address is configurable
Update README.md