Add profiles/layman.xml

Layman XML configuration file for adding the overlay to layman.
Also update the README.
Add package app-misc/cheat

With ebuild app-misc/cheat-2.0.9.

Package-Manager: portage-2.2.8-r1
RepoMan-Options: --ignore-arches
Add ebuild app-misc/cheat-2.0.9-r1

Add USE flags for bash-completion and zsh-completion.

Package-Manager: portage-2.2.8-r1
RepoMan-Options: --ignore-arches