Otherwise, we end up propagating those dependencies into targets that
link against that library, which creates unnecessary link-time
dependencies.
Also included are changes to readd now missing dependencies to tools
that actually need them.
We previously put the generated headers in SOURCES, which did not mark
them as GENERATED (and did not produce a proper dependency).
This commit moves all generated headers into GENERATED_SOURCES, and
removes useless header SOURCES.
No functionial change here, but this more easily allows for adding GUI
elements to the Solitaire window. This nests the SolitaireWidget as a
child of the main window's widget so that the SolitaireWidget does not
color the entire window green when it paints its background.
The purpose is to allow the Solitaire widget to be used in GML. The
macro to register a widget requires a namespace, so this moves all files
in the application to the Solitaire namespace. This also renames the
SolitaireWidget class to Game - this is to avoid the redundancy /
verbosity of typing "Solitaire::SolitaireWidget", and matches many other
games in Serenity (Breakout, 2048, etc.).
