Gk browser tooltip fix

Fixes tooltip freeze with very complex class definitions by using a new tooltip algorithm.
Sure, fixed.

A style question, which do you prefer:
```
        switch (property.type) {
            case RLMPropertyTypeArray:
                sub = [self tooltipForArray:obj withMaxDepth:0];
                break;
            case RLMPropertyTypeObject:
                sub = [self tooltipForObject:obj withMaxDepth:depth - 1];
                break;
            default:
                sub = [self printablePropertyValue:obj ofType:property.type];
                if (property.type == RLMPropertyTypeString && sub.length > kMaxNumberOfInlineStringCharsForTooltip) {
                    sub = [sub substringToIndex:kMaxNumberOfInlineStringCharsForTooltip];
                    sub = [sub stringByAppendingString:@"..."];
                }
                break;
        }
```