cleanup (#166)

* Remove unused import.

* Add missing documentation.

examples/doc_oHideWith.hs

@@ -0,0 +1,16 @@
+#!/usr/bin/env stack
+-- stack runghc --package reanimate
+{-# LANGUAGE OverloadedStrings #-}
+module Main(main) where
+
+import Reanimate
+import Reanimate.Scene
+import Reanimate.Builtin.Documentation
+
+main :: IO ()
+main = reanimate $ docEnv $ scene $ do
+  txt <- oNew $ withStrokeWidth 0 $ withFillOpacity 1 $
+    center $ scale 3 $ latex "oScaleIn"
+  oShowWith txt oFadeIn
+  -- oShowWith txt $ adjustDuration (*2) . oScaleIn
+  -- wait 1; oHideWith txt oFadeOut