UI: Allow user to define their own shortcuts to regions of interest

[jamiesnape]

This is a low priority, "nice to have" request from a user. We have "Greater NYC", "Manhattan", and "Midtown", but a user would like to be able to draw a region to which to zoom and then save that region. It opens up the whole customization and saved user filters that a final version of the app could/should/would have.