Move Draw::new to App module, rename Draw#setup to #run

Also moved default configuration setup of instance variables to
App.setup_default_values

These changes make the Draw class easier to understand and write without
a lot of setup in the main class.
Move position settings of chooser and picker to App helper methods.

Implementing:

* App.chooser_options
* App.picker_options

This makes writing these drawing methods in the main Draw class easier.
remove unnecessary attributes from Draw and Drawing
Use more obvious block parameter names for the position used by motion