Add expandLimits() demo notebook.

Author: alshan

future_changes.md

@@ -2,8 +2,11 @@
 
 ### Added
 
-ToDo: `geomBlank()` [[#831](https://github.com/JetBrains/lets-plot/issues/831)].
-`inheritAes` parameter in layers [[#1172](https://github.com/JetBrains/lets-plot/issues/1172)].
+- `geomBlank()` [[#831](https://github.com/JetBrains/lets-plot/issues/831)].
+- `inheritAes` parameter in layers [[#1172](https://github.com/JetBrains/lets-plot/issues/1172)].
+- `expandLimits()` [[#820](https://github.com/JetBrains/lets-plot/issues/820)].
+
+  See [example notebook](https://nbviewer.org/github/JetBrains/lets-plot-kotlin/blob/master/docs/examples/jupyter-notebooks/f-24g/expand_limits.ipynb).
 
 ### Changed