[formula] Equality operator

openformula-20070322-wheeler, section 6.3.6

The equality operator has a couple of unexpected (to me) test cases:
=ISNA(NA()=NA()) is required to be true.
I don't agree with the logic "If there's an error on either side, the result 
is an error -- even if you're comparing the "same" error on both sides.". 
That isn't intuitive, and makes for messy logic.

=“Hi”=”HI” is required to be true.
There is a note about case sensitivity, and some explanation of OOo vs other 
implementations. It seems silly to allow it to be true or false, and to still 
have a test case. The best way forward would be to state that string 
comparisons are required to be case sensitive (or case insensitive - not 
worried about the decision, just that there is one). If it has to be 
implementation defined, state that, and drop the test case.

Brad