Map - Selection shape

```
I believe Legacy Geoda used to have a way to use an irregular polygon as the
selection shape, by clicking a number of times on the map. It may be useful to
reinstate this as one of the selection options, since the rectangle or circle
may be too limiting.

```

Original issue reported on code.google.com by `lanse...@gmail.com` on 11 Sep 2013 at 4:49