Removed unused functionality, made superfluous by the new
"Privacy mode" option in the VNC Options dialog (accessible
from the Identity menu).

Now starting to use displayStrings for text content.

Using EndModal(wx.ID_CANCEL) to make it clear user canceled.

Now hides Launcher's progress dialog if parent window is
an object of class LauncherMainFrame and if it it has
a progress dialog.
Bound EVT_CLOSE to onCancel.
Now using CreateNewKeyDialog (which now makes use of displayStrings).

pass2Dialog can still be used by setting
usingCreateNewKeyDialogInsteadOfPass2Dialog to False.