Jeff, thanks for your patch and the idea.
I've tried to contruct a test that shows that the stemming will 
make searches break. However as all words gets uppercased before
going into xapian, searching for "silently" and "SILENTLY" gives
the same result, no matter if you index "SILENTLY" or "silently" 
because the word getting in the index and getting asked from it 
is "SILENTLi". So it matches okay.

Of course it does not match searches like "silent" because stemming
does not work. 

Could you create a test that fails if we do not switch to lowercase?
Does Xapian recognise this stemming issue? Or do they recommend 
switching to lowercase always?