Since some users prefer using default Prelude commands, a new global
mode is defined: prelude-global-helm-mode. When activate, Helm binds
some global key bindings to its own commands. When deactivate, Helm
removes the bindings and Prelude uses the default bindings.
The current prelude-helm only uses a single command of Helm, which
is a waste given how Helm contains many other commands. When
prelude-helm is activated, users should be able to utilize all of these
useful commands. If a user wants to use Helm, he will want to use all of
its features anyway.
prelude-helm is configured that it is able to be used with this [guide](http://tuhdo.github.io/helm-intro.html).
