[Bug 378151] Rap: Support for mobile devices

https://bugs.eclipse.org/bugs/show_bug.cgi?id=378151

Fixed following bugs:
- The detailform wrapped in the pageform was initialized twice (depending what's done in execInit of the fields, this may be bad). 
- The pageform always displayed the first detail form. If the detailform gets closed and reopened (e.g. in execPageDeactivated, execPageActivated), the pageForm needs to display the new one. 
Known issue: If the detail form (or the table) gets exchanged while the pageform is shown, it won't be updated. But this case is not very common, though. If needed, one needs to provide a propertychangelistener in AbstractPage, at the moment only AbstractOutline has one.