Factor out the code that connects to a newly created dialog and then
use that also in GuiGraphics.
There must be many other dialogs that need this same treatment....
As suggested there, we attach ourselves to the newly created inset,
if we in fact just created an inset. (This will only matter if Apply
was clicked, so the dialog is still open, but I did the calcuation
anyway, as it seems cheap enough.) This allows the user to modify
that inset (e.g., change the format) and also prevents another click
on Apply, or OK, from creating another dialog.
I've also removed the override of disconnectOnApply(). It does not
work, anyway, I think because it only works with GuiDialog, not with
DialogView-based dialogs.
In particular, the directory frontends/qt4 is renamed to frontends/qt.
Many configurations file have to be updated. All mentions of qt4 in
the source have been audited, and changed to qt if necessary.
The only part that has not been updated is the CMake build system.
