BUG in VSCR: Move window_menu to vscr

The commit "VSCR: Move window_menu to vscr" removes a curly brackets
and it creates a bug.

This patch only includes the previously removed curly brackets.
VSCR: Move menu flags to vscr

This patch moves the menu flags to vscr. Becasue rootmenu is different
between screens, we need different flags.

TODO: In next versions, after the VSCR changes, we should check if
we can move this flags to the workspace.c/h file.
VSCR: Move workspace to virtual_screen

This patch moves all the related info about workspace to the virtual_screen.
Now, every virtual screen will have their own workspace, and the workspace
is not shared between phisical screens (in Xinerama there is only one wks).