Overture missing an order/equality warning

[nickbattle]

VDMJ produces a warning if you define types with order or equality clauses and then combine them in a union that has its own order or equality clause. For example:

types
	T1 = nat
	ord a < b == a < b;

	T2 = nat;

	U = T1 | T2        <--- Warning 5019: Order of union member T1 will be overridden
	ord a < b == b < a;

These are missing from Overture 2.7.4.

[nickbattle]

Now fixed in ncb/development.