... Fix I wrote as a late 2.3.2 pull request was before I did other cuts and
pastes for cycle breaking. Replicating the patch in the new place without
extra #include directives did not compile.
... and break its compile dependency on CommandManager.h by letting it install
callbacks.
This also removes Objective-C mixed code from CommmandManager.
This also eliminates four inclusions of Project.h!
Capture handler state is also global, not per project, though the
CommandManager's callbacks still do depend on the active project.
