Verbose names for Climacons

Allows you to insert a Climacon like that:

    <i class="climacon cloud rain moon"></i>

There are two ways of choosing an climacon: either by the filename of the
corresponding SVG file, e.g. class="climacon cloud-drizzle-moon-alt",
or by picking the elements of the climacon individually:

 * `cloud`
 * `sun` or `moon`
 * If you have a cloud: add `rain`, `drizzle`, `fog`, `snow`, `hail`, `wind` or `lightning`
 * (all of the above except `wind` and `lightning` and snow are also available in alternative versions, e.g.
   `rain-alt`, `dizzle-alt` &c.)