Previously, TreeSection was drawn before TrainerSection.
Reversing the order ensures TrainerSection layout is resolved first,
which fixes scroll state being computed against an incomplete
structree page render.
Fixes#8893
For those lucky enough to have screens with a high enough resolution to
display
a chosen civilisation's tree in its entirety, the Structure Tree page
now
determines the minimum space necessary to do so, and sizes itself
accordingly.
(e.g. The page no longer scales to fill the entire screen.)
For those on lower resolution screens, the page now takes up slightly
less space
vertically.
This was SVN commit r23813.
