NGtype()
 Get the Type of an Entry
------------------------------------------------------------------------------

 Function:      NGtype()

 Syntax:        NGtype(nEntry) --> nType

 Description:   This function returns a number identifying the
                type of entry located at that Adress. This function
                is needed to know whether you are to use NGshort() or
                NGlong() for this Entry.

 Returns:       a Number indicating the Entry type. 0 indicates
                a Short List, 1 indicates a Long Entry. Any other
                number would indicate a problem in the guide, your
                application or (even worse!) the library. Suggest
                the user to re-open the guide if that occurs.

 Example:       If NGtype(MenuEntry(i,j)) = 0
                    HandleShort(menuEntry(i,j))
                Else
                    HandleLong(MenuEntry(i,j))
                Endif
                * (Assuming No errors here..)
                * (Handlexxxx are user written, of course..)

                When the NGtype() function returns a value other than 0 or 1
                (2 is also allowed, it means a Menu Entry, though it should
                not appear in the NG routines presented here) on a valid
                Entry (ie. NGmenuEntry(), NGshort()[..][2], NGseeAlso[..][2],
                NGparent()[1], NGprev().... return values), then you could
                conclude that the guide possibly contains errors. A solution
                would be to re-open the guide.