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`.
Prompts based on `mkComplFunList` and `mkComplFunList'` were not
taking into account the `searchPredicate` funtion from `XPConfig`.
This was rather confusing.
We fix it by passing `XPConfig` to these functions; although
this is strictly more than they need, it makes the breaking change very
easy to fix and is also more future-proof.
The latter is pretty useless, as there's no way to find out what
layouts are available, but it can at least allow you to select between
any layouts that you happen to be using already (in one workspace or
another). The former is handy any time you'd rather have a short name
for a layout (either for selecting, or for viewing in a status bar).
