Improvements and updates to use XFCE instead

* This guide will be updated for XFCE
* Gnome 3 is not hardened friendly atm
* Added notes on changing URLs
* Use `sha512sum` for easier checksum verification
* Adjust USE in make.conf based on previous runs
* Add CURL_SSL to make.conf set to openssl
* Fix devtempfs location
* Download kernel patch to home
* Added kernel section on USB suspend
* Removed stray nano -w command from hotplug line
* Switch from rebuilding system to rebuild world
* Added eix and gentoolkit to list of recommended packages
* Started on XFCE bit
Mostly cleanup for consistency

* Completely transition emerge system -> emerge world calls
* Standardize on category/package naming for all emerges
* Rid of old USE and CURL_SSL mentions from previous desktop guide