Covered desktop on all screens.
Fixed Main Screen 1's region being screen-dependent.
Displayed main screen on each physical screen.
Fixed alerts race condition with redrawing buttons.

There ought to be a way to check for access from the wrong thread.
Set speech indicator on all screens from console and messages.
Fixed race condition in ending alert.
Fixed incorrect desktop display on systems with negative display coordinates.
Merge branch 'Multi-Screen_Support' into 0.7.x