Add version number to root element of settings.xml

[CodesAway]

This will allow adding new functionality to existing settings.xml file without requiring users to do anything.

For example, when implement #35, would be able to add this new type. Then, existing installations would be able to use the new functionality

As part of this, add a Boolean to indicate whether the settings.xml should autoUpdate (defaults to true). This way, a user could always decide to not auto update even as new functionality was added.