templatemanager: Some items were hidden by default.

Change-Id: Iec847eb2af74442d083153c5e1f307ed32497377
templatemanager: Nobody calls setSaveMode(false).

Change-Id: Ia1844523c3ed5544b4e250c7607d2148f1c4d3cd
templatemanager: Fix empty dialog when saving templates.

We used to call just mpTabControl->Clear() in setSaveMode(); but that worked
only with .src dialogs, as the tab pages could have existed even without
TabControl containing them.  This is not possible with .ui definitions any
more (and rightly so!), so show just one tab here for now, until we do a
bigger Template manager rework.

Change-Id: I400dbcc326e883a1c1f526e94974162c3641f8ae