`SLElement` should reject ambiguous matches.

[wearhere]

If multiple matches can be found for a given predicate, SLElement should log a warning and consider a match not to be found.

Open questions:

• should rejecting ambiguous matches be optional? I'm leaning toward yes, because I guess there could be circumstances where you wanted to match one of a set of elements and didn't care which one.
• if rejecting ambiguous matches is optional, what's the default? I'm leaning toward rejecting because an ambiguous match isn't useful--it's just a matter of luck whether or not you got the one you wanted. This would be a change in behavior but again I don't think the previous behavior was all that great. This would be a performance hit though because we would have to always enumerate the entire accessibility hierarchy when matching.

[lisbakke]

How significant of a performance hit is it?

Have you guys considered a 'debug' mode for tests?

[[SLTestController sharedTestController] runTests:[SLTest allTests] withCompletionBlock:nil withDebugMode:YES];

There's other things I would find useful in debugmode, as well. Sometimes it can be hard by looking at the instruments output to figure out which line of code ran before a failure. Even though we wrap UIAElement, the problem is that we use helper utilities to do a lot of common actions, so the resulting failure always claims it happened in our utilities file.