The XS.modify was leaving thunk on the history that the demand analyser
could not prove to be neccesary as they depended on the future user
interaction. This was bad as the time advance there was less and less
neccesity to force such value, so the thunk would be increasing. Since the
datatypes that the `WorkspaceHistory` are really simple, we can just
evaluate and save a good chunk of memory.
This is a convenience module in order to have less import noise. It
re-exports the following:
a) Commonly used modules in full (Data.Foldable, Data.Applicative, and
so on); though only those that play nicely with each other, so that
XMonad.Prelude can be imported unqualified without any problems.
This prevents things like `Prelude.(.)` and `Control.Category.(.)`
fighting with each other.
b) Helper functions that don't necessarily fit in any other module;
e.g., the often used abbreviation `fi = fromIntegral`.
