introduced the Navigator interface to have two different implementation
of JFXNavigator, one trying to use builders instead
A bunch of paper.png file update popped up, boh?
the new Navigator with the makeScene() Builder-based strategy works!
Successfully removed final from certain fields.
However, two fields needs to be initialized at start up, why?
removed the two annoying initializations (by building the scene before
using those fields...)
played with Split and Scroll. A limitation of Split: it is not possible
to lock all dividers on one side together, so that by pushing one
ONLY one pane changes; that is, moving one dividers always shrink
one pane and enlarges the adjacent one by the same amount
using a Builder for the dashboard